Pioneer-12 disputes the application of the GFDL to his signed contributions on talk namespace, a fact that only became apparent to me a few minutes ago, but he has continued to contribute disputed material to talk space.
To avoid further disputed material being contributed I have blocked him--I know this is going to be controversial because he hasn't really done anything "wrong", it's just a legal dispute between him and Wikipedia, so I'm not going to engage in arguments over this, but it seems to me like the best way to limit the potential damage.