What is the potential for that taking place in an environment full of professional developers? I suppose a question could get a few upvotes, and selected as the "correct" answer, but it would seem that the vast majority of developers having a solid understanding would either suggest a better answer, or downvote the horrible answer.
In most cases it would seem sufficient to provide a better answer, and then reference your answer in the comments of the accepted answer. If your answer is better, it should begin taking on some weight.
In most cases, the accepted answers wouldn't be the accepted answers if they didn't accomplish what the author desired. That being said, accepted answers should work. That isn't to say they are the best answer, but they are at least sufficient until the best answer arrives.