I've contacted a few people to get permission to sell their patterns, all but one have had no problem, they just request that you limit the number you sell at any given time and that you give them credit for the design and indicate which pattern it is. Often they'll ask if you will send them a picture of the completed item so they can include it in their gallery. I really think that it's important to give credit where credit is due. When I see something like what you saw at a show, I just hope they're doing just that.