In my opinion this isn't a big deal. I suppose you're right from a purely structural sense. However, in reality people just want to type their answers, and often it's legitimate to present several possible solutions. I agree with Jeff, that it might be worth it to write multiple answers if they really are very different, but most of the time that isn't the case. Personally, I'm not likely to bother writing separate answers. If anyone doesn't like that, they can have all their money back they paid me to for the free advice.
