Agreed. It really should be explained clearly in the OP (of the voting topic, that is), otherwise a lot of people are going to be surprised by the outcome, I think...

With IRV (as I understand it, which is not very well), the counting process begins by considering each voter's first choice, and only when a >50% majority isn't obtained by looking at first-choices-only do the other choices start to factor into the algorithm. So, it's very important that voters think carefully about the order of their picks (IRV belongs to the so-called "ordinal" class of voting methods).

IMHO, a nice/fun way to do the voting (maybe next year?) that's cardinal rather than ordinal would be to give each voter 100 "points" to spend, and then allow them to distribute those points between (up to) 5 candidates. (But I haven't thought deeply about it, so maybe there's some result from social choice theory that invalidates this method.)