This is what you should say. It’s direct, honest and not insulting.
I have kids.
I won’t babysit anyone else’s poop container until they are at least at speaking stage.
My 9 year old son wants a friend overnight? No problem, as long as the child is polite.
You want me to watch your 9 mo old diaper dumper? No way.
It’s good but too wordy. I suggest this:
Motorgirl: Sorry, we can’t babysit.
Motorgirl’s friend: Why can’t you?
Motorgirl: (deadpan) Sorry, we won’t babysit.
Speaking as a parent, I would much prefer a communication along the lines of what Dangerosa posted than a joke about how you were going to leave my kid in a closet or the oven or whatever. That being said, there is no way in hell that I would be a parent in this situation, because after the first two or three times I asked someone to babysit and they turned me down, I’d mentally take them off my “available to babysit” list under the assumption that if they actually wanted to watch my kids, they’d have offered, or said so. These friends sound terminally clueless, seriously.
“We’re not the babysitting type. We’ve babysat twice in the last eight years and those were in genuine medical emergency situations. We enjoy your company, and it’s fine to have kidlet around when we’re visiting you, but babysitting is a whole different thing and we don’t do it.”
To me, it’s telling that these people were joyous at the thought of others babysitting for their child from the moment of conception. When I was pregnant I looked forward to holding my child in my own arms and caring for him/her … not to the time I could dump the child off on friends!
And besides, I’ve never asked a friend to babysit, ever. Family or paid high-school or college girls and that’s it. It would never occur to me to look among my friends for free sitters to mine.
And with the cat story, it seems like these people have little regard for any creature besides the ones they’ve accumulated.
Speaking as a parent (who doesn’t presume friends want to babysit, but nevermind), I wouldn’t be insulted if, when we did ask someone to babysit, they said “No, sorry, we’re just not interested in babysitting.”
No explanation beyond that is necessary, and anyone who’d interpret that as an insult is not much of a friend to begin with.
I’m king of derailing the thread here, but I was having an IM conversation related to this last night, and would be interested to here Doper’s thoughts on it.
[22:38] jacquilynne: I don’t know if it’s a big city thing or what.
[22:38] jacquilynne: People here don’t like to get babysitters.
[22:39] jacquilynne: Where I grew up, if the adults wanted to do something, they left all the small kids (not infants, but anything that was old enough to crawl) with the nearest trustworthy 14 year old and went and did it.
[22:39] jacquilynne: Here it seems like if you can’t get a relative or close friend to look after your spawn, you stay home.
Is this the case where you are, Motorgirl? And does anyone know when 14 year olds stopped being trusted with children?
I am also agreeing that these friends are the far side of clueless, and you can keep doing avoidances if you want, but really, you are perfectly within your rights to simply not want to babysit.
All the conversation you need to have next time they ask;
Clueless friends: “Can you babysit this weekend?”
You: “No.”
CF: “Why not?”
You: “I’m not interested in babysitting.”
CF: “Whatever babble they might try on you at this point.”
You: “I’m not interested in babysitting.”
Repeat as necessary. You don’t need to explain yourself or make excuses.
(For the record, we have family members come in to look after our cats when we go for longer than a weekend. Even free-feeding cats do need some looking after. We don’t expect people to play with them for an hour and come in twice a day for free, though - I’d expect to pay someone for that kind of service. I just want someone to come in every couple of days and make sure they’re still alive.)
Ann Landers (or maybe it was Dear Abby) once said, “No one can use you for a doormat without your permission.” 
What’s wrong with a simple, “No, I don’t want to”?
Now that I’m old enough to have been used for a doormat many times in my life, I’ve finally gotten tired of it, and I’ve used this response successfully many times when someone asks me to do something that I don’t want to, from decorating gyms for proms, to playing the piano for choir practice, to babysitting, to allowing my Sunday School class to be combined with another entire class because they can’t find a teacher, to running the church nursery (just shoot me first, really).
I simply smile kindly and say a little ruefully, “Naw, I don’t really wanna do that…” And if they press the issue, I simply keep smiling and repeating, “No, really, I don’t want to.”
The trick is, you have to not care that your rejection of their agenda might make them Hate You Forever or otherwise offend them or hurt their feelings. I’m not a rude butthead about it, but sometimes I simply politely decline to go along with the current program, and the way I see it is, if that chaps their hide and they choose to vindictively strike me from their Christmas card list, well, so be it. Anyone who would be offended because I told them I didn’t want to do something that they thought I ought to do is not someone who is a true friend.
But we’re brought up to be polite little ladies, and to be helpful, and when someone asks you to do something, you’re programmed to want to help them out, so you say “yes” automatically, even though you hate yourself for it. We’re taught that it’s rude to reject people flat-out, so we waffle and look for excuses, but the fact is, it won’t kill someone to say “no” to their face.
The trick is to not care that you can’t help them out–the trick is to not care that saying “no” to a combined Kindergarten, First Grade, and Second Grade Sunday School class means that the Children’s Ministries lady has to go and find more teachers; sadly, I’m not going to be able to make her happy and bail her out. And that’s too bad for her, but the tradeoff for me, should I accede to her plan, would be a year of Sunday School hell, and so I dig in my heels and refuse to help her.
So that’s what it boils down to. You’re going to have to resign yourself to not being able to help these people, and to the fact that they might Hate Your Forever if you refuse to help them.
So, just say no. Smile. Keep saying “no” and keep smiling.
Actually, yanno, toddlers are a real hoot. You might have a good time. Babysit the kid at their place, not yours, because their place is presumably already child-proofed. Nobody expects you to “love” the baby, or to invest yourself emotionally in it, any more than if you watched somebody’s dog for a weekend they would expect you to be oozing with maternal love towards it. All that’s expected is that you “mind” it, as in “make sure it doesn’t hurt itself, and call 911 if the house catches fire”.
And minding a toddler, assuming a child-proof venue, is dead-simple: just hand it a new toy every couple of minutes, keep an ear tuned for crashing noises or ominous silence, then go back to your magazine or DVD. See, the trick in babysitting small children is to go ahead and do what you were going to do anyway, but maneuvering around them. They carry on in the background, requiring only occasional maintenance (diaper, snack, nap, story, “oh, that’s nice”, “don’t touch that”, “oops, give me that” comment), while you knit an afghan or read your book or pay bills or wash dishes (all of which, you’ll note, are interruptible things. You can’t study for a chemistry exam while babysitting, but you can read a book). In other words, you’re not required to sit there for three hours solid with all your attention focused on the toddler, because your brain will explode with boredom. Just get on with your life, keeping a weather eye on the kid.
“I’d love to, but the court order specifies that I can’t be alone with children.”
Seriously, you’re going to have to say something like “I’m sorry, but we’re just not good with kids.”
If you want them to stop asking, you do need to explain that much - since these people apparently don’t pick up hints and are persistent. But you can certainly just keep saying “no.”
Why should this be “expected” of someone who has clearly stated that she is not interested in watching kids? Seriously, I would far, far, far rather that someone just tell me, “Sorry, not interested,” than grudgingly watch my kids on the assumption that it “might turn out to be fun” and all they have to do is call 911 if the house burns down.
1 Babysit the kid.
2 Get the baby a tattoo.
3 Never babysit again.
If you just keep “having plans”, which Ann Landers taught us never to elaborate (perhaps your plan is to watch netflix movies), then they will get the hint.
Some people are more insensitive than others, and will continue longer, but Sorry every time means you will never have to sit.
Um, I meant the argument would be like a TV soap opera! :o
But they are a source of excuses too…
Them: “Can you babysit this weekend?”
You: “No thanks.”
Them: “But we can’t get anyone else!”
You: “Sorry.”
Them: “But you haven’t explained WHY!”
You: “Can’t. Sorry.”
Them: “But WHY?”
You: “Sorry.”
Don’t give them anything to react against. This is not your problem to solve.
Regards,
Shodan
It sounds like there’s been some sort of miscommunication - could they be mixing you up with someone else that expressed a big interest in babysitting? It sounds more like they’re convinced that you expressed interest rather than just taking advantage.
**
But this has been going on for 6 months**. Excuses haven’t worked, so why wuold polite refusal?
Um, because I thought–reading between the lines–it sounded like she was saying, “I’m intimidated by the idea of watching kids younger than five”? Some people are, and if that’s the case, I thought I’d make a suggestion.
I myself was totally intimidated by babies–actually, by kids, period–never having done any babysitting other than a single outing when I was 14 which did not go well. Which made things pretty interesting the day my mother went back to Illinois and left me all alone with a new baby. 
So I was just sayin’, yanno?