[ncray]

Let's just say that having absolutely no idea is the same as randomly guessing (pick each of the 5 answers with probability 1/5). So, by randomly guessing your expected score is going to be 0. Why are you assuming that people are going to have the 'slightest idea' (probability > 1/5 of getting the correct answer)? This assumption obviously bumps us up to > 0 expected score.

This might be true for poorly designed questions, but it's very easy to come up with trick questions or more difficult questions where fewer than 1 in 5 get it correct.