I embarrassed myself at a conference by asking an irrelevant question. Does this happen regularly?
If the question is "do most conferences have a few bad questions", the answer is certainly yes. People are likely to forget bad questions, more difficult to recover from a bad talk. I've been in quite a few conferences where someone (often a student without adequate guidance) would give a bad talk and everyone would be talking about it for days. I've also been to conferences where most of the talks were thoroughly forgettable and you would have to light the podium on fire to attract negative attention. I don't ever remember hearing people complain so vehemently about a bad question, only a bad talk. 

The main "bad question" is one that is too basic for the audience ("what do you mean by calculus"?) or reveal a basic lack of understanding ("could you address heat dissipation by using logarithms?"). Questions that are too technical are rarely a problem unless it's way off-topic or takes up too much time.