Let me give an argument in favor of #4, doing what the others do, in the thermometer problem. Now we seem to have them behaving badly. I think in practice many people would in fact look at other thermometers too in making their guesses. So why aren't they doing it? Two possibilities: they're stupid; or they have a good reason to do it. An example good reason: some thermometers don't read properly from a side angle, so although you think you can see and read all of them, you might be wrong. (This could be solved by #3, writing down the average of the cards, but that doesn't work if everyone tries it since everyone is waiting for everyone else to go first.)

Only if we add a stipulation to this problem, that you are usually right when everyone else is wrong, would it be a good idea to buck the crowd. And even then there is the danger that the others may have some private information that supports their seemingly illogical actions.