Actually, I have considered a cotton bag. I've already picked one out, and will be ordering a 200 next week. I actually already have 3 retailers currently waiting for the blocks in fabric bags as it drops the the retail price a bit. Perhaps that would be a way to go. Either that or just have the bucket tested. It's amazing how much more money a retailer will charge just because of the bucket.
If a product is not tested, who is liable if it is in violation, the manufacturer or the retailer selling it? I've heard that it would be the retailer. In the case of Etsy, it would also be me!