I stopped participating in swaps, not because of fabric quality, but because, after three trips through the washer, I could still not get rid of the stale cigarette smell in the last fabrics I received. :shock:
As for quality, if the receiver does not want to use "inferior" grade fabrics in a quilt, they can use it for trying new blocks or techniques, a pet quilt, or swap it again with someone else. It's that old looking a gift horse in the mouth thing as far as I'm concerned.