I once bought a pattern for a wheelchair lap quilt. It was a simple pattern. I could have made it just by looking at the product on the internet.
However, when I got the pattern, it said I was not allowed to sell the lap quilt I made from the pattern. I contacted the seller and told her to refund my money, as I was not willing to abide by her "rules".(My sister is a TAG teacher. Her 5th grade students had a module on quilts. I helped her, as she doesn't sew past hemming a skirt. The kids donated their lap quilts to a Church for their needy.)
Even if she was able to enforce her rule, all I would have to do is change one little thing and her "copyright" wouldn't apply (make it 1 inch larger or add a pocket). The idea that someone thinks a copyright on a quilt pattern is enforceable is nuts. Is she/he really willing to hire a lawyer, and take you to court to enforce his/her copyright. It's just too expensive and the most they would get is a "cease and desist" order.
If you put a "c in a circle" on a quilt pattern, most people will abide by it and not copy the pattern and sell it. To go further than that is not reasonable. It's especially unreasonable when you don't state your additional rules/terms up front.
bkay