Personally, I think it would be a shame. You're only on the hook if you want to modify their reference implementation, and aren't interested in sharing your cha

Personally, I think it would be a shame. You're only on the hook if you want to modify their reference implementation, and aren't interested in sharing your changes with the community. Write your own implementation under whatever license you want (and once they're a little farther along with actual protocol documentation, that ought to give you everything you need to make it happen), or share nicely. I'm not sure how that's a problem.