[scromar]

Edit: Now I think I was wrong in this reply. I did not realize that paragraph 4 of the agreement gives the inventor the right to license the patent to another party to enforce the agreement. However, the broad language of the second paragraph still gives the assignee a lot of wiggle room to argue that they are not breaking any promises made.

--- Original comment:

I mentioned this in another thread, but it is actually simpler than that. As I read it, the twitter agreement gives all rights in the patent to the assignee, just like any other assignment, but it adds on the clause that the assignee agrees to get permission from the inventor if they want to sue offensively with the patent. In the future, if the assignee (whoever it is at that time) decides to sue offensively without the permission of the inventor, the assignee can (and indeed they have the right to, as the holder of all the rights in the patent). The inventor would then have a cause of action for breach of contract against the assignee, but who knows what that would amount to.

Basically, I doubt that a court would read the agreement in a way that prevents the future patent assignee from using the patent offensively, even without the agreement of the inventor.