If it's a kit or a pattern that you followed to the letter, then that's one thing, but once you start doing your own thing with it, how can anyone claim copyright? I rarely buy patterns and even more rarely actually follow them. Somehow or other mine is not going to look just like the pattern.
Then again I see pictures of all sorts of quilts and totes and eventually one I've made is most likely going to be pretty much like one somebody else made using some pattern, even though I just did my own thing.
So it becomes a real conundrum.