There probably wasn't, actually. And even when present, players tend to ignore those clauses anyway.
reminds me of when "Indian Larry"(bike builder and stunt man) died... he wasn't wearing a helmet either :\
I have a vague recollection of one of the Pittsburgh Pirates being interviewed on a sports talk show shortly after Thurman Munson's plane crash saying that he could not fly without team permission....I realize it would be difficult for the team to monitor such activity....although if a player in breach of his contract were to be caught in the act...I suppose he could be docked pay...this is a heck of a way to be caught in the act though...