The point of the scenarios RE: the tram is knowing - or trying to know - how you would react in that exact scenario if you had exact knowledge & certainty of the consequences. It is not intended to be realistic in the sense of uncertainty about outcomes, it is a test of how you value those outcomes given the actions required for each and the consequential responsibility you would feel you held.
Yep, they are overly simplified scenarios, I can agree to that. And that's why I think they fail to do what they should (to collect information about ethic decision making in theoretical situations), because they are thoretica lsituations badly hooked to real world. By tho poll results I think it's safe to say that almost all who come across this problem first think it like that - through possibilities, trying to automatically find holes out of the horrendous situation.
In this example I said it cannot be known that the trolley will hit the group of five, or the single man. And there is no way a person could actually have full knowledge of the consequences during the decision. And, as people tend to link imaginary situations to real life, they handle the thinking test that way, too. Most people automatically realize that by turning the switch they reduce a possibility of accident and also reduce the worst possible outcome. They (like I) also find it very disturbing idea to personally push the fat man to the tracks to stop the five men from dying. That is also because they automatically understand that if they push the man down, he is certainly dead, but there might yet be a possibility that the five men hear the trolley and get out of the way.
A better example would be like this (nothing personal, Carl - you just happened to snag my lunch yesterday

) :
Carl, our resident Shivan, has in his mingled mind made a plot to measure the ethic build of human race. He has emprisoned all HLP forumites in a Sathanas - exept for you and [a random HLP forumite]. He explains to you through ETAK that you can easily save all other HLP forumites - but you must personally kill [a random HLP forumite].
What do you do? If you refuse to kill [a random HLP forumite], Carl the Shivan sets the Sathanas off to a nearby sun, destroying all the HLP forumites exept yourself and [a random HLP forumite], leaving you vulnerable to vicious n00b attacks asking about FS3 and with endless questions about getting some mission or a model to work... (well, there's always karajorma's faq so it wouldn't be so bad, but still).
On the other hand, if you do Carl the Shivan's bidding and kill [a random HLP forumite], all other forumites are saved from the Sathanas and are able to return to forums. You know Carl the Shivan does not lie to you, because he has no need to.
EDIT(for audience's request): You have been almost totally paralyzed by a Shivan drug (their version of spacecrack) and you can only move your right index finger to press button A that kills [random HLP forumite] and B that sets him free and causes the death of everyone else on HLP.
(did you really think Carl would be that easy an opponent? Really, "attack a shivan", we saw that in Hallfight.

Also, the captured HLP forumites are under the influence of the same Shivan drug so they too can't do a thing (except wave their index fingers and occasionally middle fingers, too).
What is your fateful decision?
