Q: seems redundant to me. Is there a reason I should not remove it from every question title I come across?
Q: is, in some way, related to the question itself, it should be removed from question titles, after all, questions are the only thing that have titles!
If you don't have the reputation to edit questions without sending them through review make sure you check the body and tags of the question for other things that need fixing. The chances are, if the title contains
Q:, the body will have other things that need editing as well.