I think it also depends on the class size. If there are only 10 students, then it's very risky to pick 6 points, since you have to be the only one who picks it. But if there are 1,000 students, then it'd make perfect sense to pick 6 points. Basically, the less of an effect your own decision has on the group outcome, the more rational it is to pick the selfish decision.

This is why I find voting hard to justify if you view it pragmatically (even though I do it). It's mathematically improbable that my vote will make any difference. Then why do it? Sure, if everyone thought that, it would be bad. But it doesn't matter what other people do: your vote still won't matter either way. It's such a huge pool of voters that it's literally impossible to put yourself in a position where your vote makes a difference. Basically, it's important that people vote. But it's not important that a particular person votes.

Can anyone convince me why I in particular should vote in an election of a quarter billion people? Are there any reasons other than following idealistic principles? I mean, following principles is important, but I was wondering if there are more pragmatic arguments.