I would assume that this wouldn't get you very far in court since it is not at all clear that the value received will be considered "consideration" for the purposes of a contract. The issue I have is the permanent nature. Without the permanent nature, if it just has the language of the first and second releases posted by David, there is no need for consideration to have been received, it is not a contract, only a statement of permission being granted.
Originally Posted by copake_ham
Edit: I am not a lawyer, I have just read enough to be dangerous.