Including the designer's name may not be "required" on quilts made for sale, but it is certainly the courteous thing to do. What IS required is an FTC (Federal Trade Commission) label that gives fiber content and country of origin; care instructions are also usually included. The law covers the 'hobby seller' right along with Martha Stewart. Buyers have a right to know what the quilt is made of and it's a simple thing to do.
http://business.ftc.gov/documents/bu...-and-wool-acts