I think what the hostess of this possible future swap is talking about is actually "cut your own" 2.5" strips instead of buying a jelly roll and putting it in an envelope, buy yardage, wash it, dry it, cut it into strips THEN send it off. At least this would be the ONLY way I would wash 2.5 inch strips! lol I lose color catchers in the washer, much less 2.5" strips. lol It wouldn't be different than washing fabric for any other swap.
I too am a non-washer, but many people can't handle unwashed fabrics and I am sure that is the reason for prewashing.