I'm curious about the "sex" exception in "don't use your bed[room?] for anything except sleep and sex". It strikes me as unprincipled. Have they actually tested "doing this in bed is bad for sleep, doing that in bed is bad for sleep, doing the other in bed is bad for sleep... oh, but doing sex in bed is okay"? Does masturbation count?

I mean, it might be a case of anticipating "we have nowhere else to have sex, and we're not giving up sex" and making an exception so people will be more likely to follow it. But then I feel the better exception, at least for certain audiences, would be "don't use your bed for anything that you can conveniently do in other places, except sleep".