I don't recall signing that, but I'll take your word for it. You'll probably say something silly like merely buying the CD is agreement to the license. It sort of like sending a check to the city of San Francisco for a dollar, with a inscription "payment in full for the golden gate bridge", then claiming that since they cashed the check it was a sales contract.
Let me cut to the chase here:
The record industry is in a panic now, because they have discovered that they've been selling the wrong thing the whole time. They thought they were selling music, when in fact they were only selling records, and then later CD's. They were selling little pieces of plastic, because nobody's been able to figure out how to make money off of music itself. They only think they're in the music business. No, they're in the little round bits of plastic business, and now nobody really needs the little round bits of plastic anymore.
They're fully correct in being in a panic, but there's a reason that the "R" in RIAA stands for "Recording". It's not the "MIAA", and maybe it should have been.
You don't have to sign it. It's a copyright reservation of rights statement. And the Uniform Commercial Code says you agree to that when you buy copyrighted intellectual property.
To really cut to the chase, forget about the RIAA. It isn't even part of this issue. Simply because you can't tell the difference between the disc and the contents of the disc doesn't change the law or the rights of those who create music.