Let me cite these two examples. Some years ago one of the sewing machine companies digitized a series of truly original quilting designs and sold thousands of them........A direct copy. The designer sued and won.
Another took an existing stencil which was also original and changed the middle and started manufacturing. Said they could do it because they had changed it 30%. The copyright attorney said no. As long as it can be recognized alongside the original it is a copy. He said there is no such things a changing it a certain percent....
Another bought stencils and started marking and printing them as paper patterns. Even wrote a book and put them in the book. Sold dozens in every class. This is an issue that should be defined by a knowledge copyright attorney who knows our industry so we can stop the "10 blind men describing the elephant" method of deciding what is right and what is wrong. Many years ago I made a small tree wallhanging from half square triagles. Nothing special but I did it. The next year I saw a pattern at a show and said to the owner "that looks like my wallhanging that I showed at another show. She said "Yes that is where I saw it and got the inspiration to do a pattern".......So to say "its out of control, just ignore it" is not the answer. It is not only the courteous act to ask by may the legal thing to do.
We need a defination of what those words on the selvedge really mean. And designers need to stop putting a copyright on every nine patch pattern they "design", unless there is something very unique about it, which I can't imagine what it is. If the copyright means one can't copy the pattern and sell it or share......that is one thing.....or copy the instructions and pass it out free in a class or to their guild, then that is another. Now off the soap box.