I've certainly shared patterns with individual quilters, especially if they are old - the patterns that is not the quilters!! No money changes hands, and credit is always given to the originator.
In a lot of cases, a "pattern" is not original - its made up of well known blocks - the particular layout or the colours chosen are what makes it unique, and this can be an inspiration to others. I don't know who owns the "copyright" for say the nine patch or Jacobs Ladder or Ohio Star or any other well known block. In terms of actual quilting, we all copy and use feathers, scrolls, flowers, stars, leaves etc, and nobody ever thinks of a breach of copyright.
If you go to a website like QuiltersCache, some of the block patters are marked as "original" and the user is asked to respect that - ie don't pass it off as your own, and try and make money out of it.
Just my thoughts on the issue - haven't taken legal advice or anything!!