As a former librarian, I try to keep within copyright laws but when I quilt, I want my (sometimes plain and very not perfect) quilts to be MINE. For this reason, I avoid panels unless I am doing charity quilts for children and even then I like a more generic panel.
I find it really small minded to slip a logo into something that will garner free advertising. A nephew won't even allow a car dealer to put his logo on the back when he buys a new car. He's a Public Relations Specialist and REFUSES on principle to provide advertising for anything for which he's not reimbursed.
Maybe you should submit an advertising bill with a letter of complaint to RealTree (or whatever the culprit is)!