Being Asian, sleeping on the floor isn’t an issue and actually for years was where I slept. But in the movies and TV, people will go to great lengths to make a too small tub a bed. Has anyone actually done this is real life?
Not on purpose.
I grew up in a house with an old fashioned claw foot bathtub, you could easily sleep in it. Not that I did, but you could.
I’ve heard of children sleeping in bathtubs in bad parts of US cities because of the risk of drive-by shootings. I have no cite, but I sorta thought this was widespread knowledge.
I went to a sleepover as a teen. Think: 8 squealing teenage girls, and the Mom of the party giver in her cups and riotous fun ensued. After we snuck out and went and peeped at a boys house on the next block. Got chased home by a large dog, somehow I ended up in the bathtub asleep. I got treated to a cold shower in the wee hours. Caused screaming and laughing. It woke up drunk Mom and she called everyones parents to come get their kids. My Daddy was not happy with having to drive across town at 4am. And I was wet, head to toe.
So, really, bathtub sleeping wasn’t the most exciting thing that happened at this party.
My bathtub is my emergency retreat in case of a terror attack.
Grab my laptop and pillow. Turn off all the lights. Stay quiet until the helicopters come. The bathtub is low to the ground and has more walls around it that the main room.
My Japanese friend told me that only a barbarian would wear shoes inside, or go barefoot outside. I suspect that the trope derives from the understanding that it would the only available clean surface in the house.
Note that it is entirely an American trope. American frontier houses had bathtubs and dirt floors. That was not a common combination in Europe.
However, that doesn’t mean that anyone ever did it. Only that it would make more sense to theatre audiences than the idea of sleeping on the dirty floor.
I once slept on a billiard table. I will gloss over the circumstances but it was that or share a bed with a rather drunk friend. Back in the day, billiard tables were the ‘normal’ alternative rather than baths.
Also, Americans had the well-known characteristic of chewing tobacco, and spitting in, around, near to, or in the direction of the spittoon. Or dribbling on the floor, as circumstances dictated.
John Lennon?
My 80-lb dog, for unknown reasons has twice slept in the bathtub. Freaked me out the first time because I couldn’t find him in the house, then went I took a break from looking, went to the bathroom to do business and there he was. Goofy dog.
But, no, nobody I know has ever slept in the bathtub on purpose. I’ve fallen asleep while taking a bath, but that’s about it.
Have only dozed off on occasion when soaking in a hot and bubbly bath. To actually make one’s bed in a bathtub is something I would never do. I’d rather put my seat back and sleep in my car if I had to do so.
One nightmarish unforgettable night. In 2004. I was living in an apartment with my ex-gf. I don’t even know what exactly happened (that aspect is long forgotten) but I think it had to have been some form of food poisoning or the like. Anyway, I came down with explosive uncontrollable diarrhea. She took me to the ER. They basically said Imodium is what we can give you. All the while the diarrhea is continuing unabated. So I decide to test the waters (pun intended) at home with a bottle or two of Imodium AD.
Well it was a gruesome experience. In my experience up until that time, Imodium had always worked relatively quickly, like in a hr, max. But this was no ordinary diarrhea. No sir. This was diarrhea from the black lagoon. I simply could NOT stop. Ultimately, I said fuck it! I crawled into a extra-large Hefty Cinch-Sak, and laid down in the fucking tub for hours until this shit fountain deep inside my colon was finally empty. I didn’t DARE let my girlfriend enter the bathroom that night. Thankfully we had 2 bathrooms. Otherwise she woulda been pissing in some Evian bottles. 
I had a friend of mine sleep in the tub for a month or two.
It was a tiny apartment to start off with. My friend–a different friend than the tub-sleeper–liked to live frugally despite the success of his job; he worked downtown but any apartment within easy distance of work comes with a price premium. His apartment was precisely big enough for one person. You could touch any two walls in the kitchen with outstretched hands, were so you so-inclined and taller than three apples.
Flush with success, though, he shipped his beau over to live with him. People can live in cramped quarters and they did, and since he was gone for days at a time anyway, it wasn’t quite so bad except for those days when he was around. She was often in risk of going stir-crazy, so it became my job to make her days a bit brighter when he wasn’t there. They shared the bed but they were an item, so that was okay.
There was a living room of sorts, but it wasn’t much bigger than the kitchen. A person could touch any two walls there, were they so-inclined and suffiently broad of armspan.
Well, then my friend’s brother–also a friend, and adding to the confusion–and a rather tall and built man who later had a stint as a pro rassler–came to the city to try his fortunes here. It’s one thing to share a bed with your beau, but it’s another to share it with your bro. The living room wasn’t going to cut it. So that left the bathtub.
And that’s where he slept until they all moved out together to significantly more spacious arrangements.
[Moderating]
There’s some “what is the origin of this trope” here, and that could go in GQ, but the OP is structured as a poll, and that’s what most of the responses are, so let’s move it to IMHO.
[Not moderating]
When I went to an overcrowded sleepover as a teen, with bedding space scarce, I ended up sleeping in a living-room chair. Not even a recliner, but it still seemed the best option available. I just pretended I was a cat.
Much less drama than Beckdawreck’s, but then, my host-mother was sober.
Can you give an example? I have no idea what you’re talking about. People are turning their bathtub into a bed for sleeping? This is common in movies and tv?
I’ve seen the sleeping-in-a-bathtub scene in movies and TV shows and it didn’t make sense to me either. For one thing, you have sleep sitting up and also the tub is going to be really cold, particularly if it’s cast iron or porcelain.
She told me she worked in the morning, and started to laugh
I told her I didn’t, and crawled off to sleep in the bath
I did it once or twice when I was sick with buggies that clotted up my head with congestion and gave me a horrible splitting headache. Immersed in a tubful of the hottest water I could stand was by far the most comfortable place I could put myself. (submerged my head for long counts but opted not to intentionally drown). Fell asleep in there from exhaustion.