|Don't ask to ask, just ask|
Oddly enough, I had a conversation about this with my wife this weekend, on the way to a wedding reception, where we were debating what we 'ordered' on the RSVP cards.
She said something along the lines of: "I think I put you down for meat, and I think I put myself down for fish." Naturally, I responded "Isn't fish meat?". The answer: "No. Well, yes, it's a type of meat, but it's not meat, it's fish."
So there is definitely some set of people that think that meat == beef, pork, or chicken, and vegetarian == non-meat. To some of these people, non-meat includes fish, which makes no sense to me, but oodles of sense to my wife. Possibly because she hails from the east coast of the US, where seafood is plentiful, and needs to be classified differently from normal midwestern fare such as beef, chicken, and pork. Which are all meats. But not seafood. Thus the strange non-meat distinction.
I asked her very kindly to refer to non-seafood 'meat' as either beef, pork or chicken - but no, those are meat, while seafood is fish. And not meat. Which I do not understand, but understandably have to accept.
Suffice it to say that some vegetarians (perhaps our own ysth included) consider fish a non-meat meat, and thus don't include it on meat v. non-meat polls.
Update:Oh, and due to the above, I have no idea how my wife would answer the poll for Christmas, where her family observes the (italian|catholic|east-coast) tradition of the "Feast of (nearly) 7 fishes", where they feast on several (up to, but never more than, 7) types of fish, none of which I particularly care for ;-)