This is just an educated guess, but I am fairly certain that this wouldn't hold up in a US court if they were to sue over it. Banning something as broad as a l

This is just an educated guess, but I am fairly certain that this wouldn't hold up in a US court if they were to sue over it. Banning something as broad as a link to a website would probably run into serious first amendment issues. Further, they probably would never sue over it, because once they test in in court and lose, then the clause is demonstrably invalid. If it's never tested, they can still use it in C&D notices to try to intimidate people.