The correct reply, I think, is (d) it all depends.
Bring the bar down to a lower level and consider this: if you are a mom faced with two squabbling children, when do you intervene? The answer is, it all depends. It depends on how old the children are, it depends on how they’re fighting (with words, or with sticks and stones), it depends on how long they’ve been going around and around, it depends on how ugly it is, it depends on how tired and fed-up you are, it depends on what the consequences might be if you simply did nothing.
In the Wide World, MYOB obtains in a big way, which is why the people in the room next door at the Radisson did nothing other than knock on the wall. Most of us are resigned to the unpleasant fact that for every time you call 911 and report excitedly, “I think a woman is being murdered next door!”, and the cops break down the door and find that, yes, a woman WAS being murdered and that you, by your timely phone call, have saved her life, there are going to be at least 20 times that the cops will break down the door and find–two people having really hot sex. Or a prostitute being paid to have “really hot sex”, and she won’t thank you for bringing her existence to the attention of Hotel Security. (Neither will the john.)
So we all learn the hard way to mind our own business, and sometimes that makes it difficult to tell when someone really does need intervention.
Sometimes, also, you try to help somebody and you get your head bitten off, or at best, you have a very strange experience. The woman you vaguely recognize from church whom you see wandering around the mall parking lot may not be looking for her car at all. She may have just found out that her husband is cheating on her; she may be bi-polar depressive and have just gone off her lithium; she may be looking for her son’s car so she can put a note in it telling him the Vietnamese girl he apparently “knew” in 1972 has turned up at the house, and did he know he had a son? If you go bustling self-importantly up to her and announce, “Hey, Mrs. Smith, your car’s over there!” at best you may get a “Gee–thanks…”, but at worst she may jump all over you, “mind your fing business you cs*ing ct…” Better just to say “hi” and let her tell you if she needs help.
Same thing for the husband and wife arguing–it’s more than likely that they’ll abandon their fight and gang up on YOU.
And then there’s the unpleasant fact of life that many people nowadays carry guns, and that criticism, no matter how constructive, may possibly be answered with a couple of .38 slugs to the chest. “MYOB, you SOB!”
See?
And as for telling a pregnant woman she shouldn’t drink coffee or vodka–well, sometimes pregnant women carry guns, too…