I can understand mass production from a pattern --- as in the case of Disney. I wouldn't buy a pattern if I could just go to the store and buy the quilt for a fraction of the cost of making it myself. However, I doubt seriously that designers care that much about someone who is selling a quilt or bag at a craft bazaar. It wouldn't be worth their time or effort to sue someone.
That being said, this makes me feel like my quilts are not really my own anymore if I use a pattern.