Here is a site that might explain pattern copy right issues. I thought I found this on this list but maybe not so I will share it . I keep reading the questions you have.
Lots of information.
Backed up with court cases.judy j
http://www.tabberone.com/Trademarks/trademarks.shtml

Judith, I'm having a hard time sorting through this guy's bitter rhetoric. Can you point me to the place where it talks about SPECIFICALLY quilt patterns and their use?

There is a lot to read and yes a bit bitter but there are court cases he lists to prove his fact.
I have read so much there at different times I'm not sure what you want but here is one page that might be helpful.
http://www.tabberone.com/Trademarks/...Quilting.shtml

and another
http://www.tabberone.com/Trademarks/...htMisuse.shtml

I found First doctrine sale interesting.If you have the time click on the highlighted words and you will get more information than you probably want to know.
http://www.tabberone.com/Trademarks/...irstSale.shtml
index

Index
http://www.tabberone.com/Trademarks/site_index.shtml
judy j

Oh and I should have said I have not read about the quilting
copy right.i will when I have more time.
judy j

thank you for this thread, the site is very informative