I haven't done a swap on this board but would be open to do one. I'm neither a smoker nor a pet owner, but I wouldn't be offended to receive a block from someone who is. I can always wash them. My primary problem with swaps at my guild is that the blocks usually aren't all the same size. That makes them hard to put together, but even that can be gotten around. The fun of swapping makes it worth the small inconveniences.
I've just joined a swap on Carol Doak's online group.
My guild does something we call "Block of the Month," but what it really amounts to is a raffle. Everybody makes the designated block and one member wins them all. I love it! I've won it 3 or 4 times in the last 5 years, and most of them are still UFOs! :)