I might be mis-remembering, but doesn't (L)GPL rely on copyright law for its status? If so, then there's at least one bit of IP that's "properly protected" by copyright law.
I don't have a link but my impression is that part of the need for the GPL to exist in the first place is due to restrictions of copyright and the GPL uses copyright to enforce itself as a way of reacting against the system which it would rather not exist.