I agree also, keep as a request, as we all try to do our best to follow. When I'm not sure I will pm the swapper to get feed back, usually sending a photo of the fabric I have in mind to use just to double check.
I've been doing scrappy quilts for a while since I am trying to use up my stash of fabrics. there are times when I think that colors don't go well together in a block but when it is part of the full quilt it all seems to work out.