A conference on software patents and free software

I can't see how. It's basically a big patent pool that will enforce its patents against anyone and everyone unless they cross-license all of their own patents. You have things like that in industry already. If MPEG-LA doesn't run afoul of antitrust law, I don't see how this would. You'd only run into antitrust law if you tried using your patents to drive competitors out of business or something, I'd think. Not if you simply demanded cross-licensing. Look at AMD and Intel.