I think implausible hypotheticals are often intuition pumps. If they are used as part of an attempt to convince the audience of a certain point of view I automatically get suspicious. If the point of view is correct, why can't it be illustrated with a plausible hypothetical or a real world example? They often seem to be constructed in a way that tries to move attention away from certain aspects of the situation described and thus allow for dubious assumptions to be hidden in plain sight.
Basically, I always feel like someone is trying to pull a philosophical sleight of hand when they pull out an implausible hypothetical to make their case and they often seem to be used in arguments that are wrong in subtle or hard to detect ways. I feel like I encounter them far more in arguments for positions that I ultimately conclude are incorrect than as support for positions I ultimately conclude to be correct.
That's interesting, and might apply to the trolley problem which implies that people can have much more knowledge of the alternatives than they are ever likely to have.
Ethical principles and empathy (as a sort of unconscious ethical principle) are needed when you don't have detailed knowledge, but I haven't seen the trolley problem extended to the usual case of not knowing very many of the effects.
It might be worth crossing the trolley problem with Protected from Myself.
Taking a look at ethical intuitions with specifics: Sex, Drugs, and AIDS: the desire to...
It has been claimed on this site that the fundamental question of rationality is "What do you believe, and why do you believe it?".
A good question it is, but I claim there is another of equal importance. I ask you, Less Wrong...
What are you doing?
And why are you doing it?