Just because a quilt pattern maker tries to limit use of their pattern to hobby quilters beyond a standard copyright clause doesn't make it legal. And just because some magazine or blog suggested that you write the pattern maker for permission to use the pattern to sell a quilt or that you are required to "credit" the designer in writing doesn't mean you are legally bound to do so. When you buy a pattern from a designer, you haven't entered into a contract with them, you are only bound by laws and regulations.
This whole issue makes me so mad. When someone makes the decision to profit from their designs by selling patterns they cannot control what the consumer does with the pattern, beyond prohibiting selling copies of the pattern itself or using it for mass production. They have given up exclusivity, it is no longer a one-of-a-kind design.
I'm with those who have started reading the fine print. Even though I don't sew for profit, I will no longer buy any products from designers that attempt to limit usage beyond copyright or trademark license.
P.S. I'm not a copyright or patent lawyer, so this is my opinion.