If my guess is wrong, I'll get jumped on and usually that means I get the right answer in the process. =) In fact, the more ridiculously wrong I am, the faster I get a response XD To a point, of course. I try to make sure that my guess is a good one that's backed up by at least common sense and some Google-fu if I can manage it. It would be pretty easy to end up looking incompetent.
I'm taking advantage of peoples' innate urge to rectify and redress anything in their domain of knowledge that someone else has bungled, perhaps badly. =)