If we are going to use this metaphor, its not about putting a lock on the door but having a door at all.
You need locks to protect yourself from malicious people, you need a door just to indicate that people shouldn't randomly come in. MIT is like not even having a door. There is no point in buying a top of the end lock if you leave your door open and hang a sign saying free cookies.
I would also disagree that hard power is the only possible way to defend one self. Soft power has its place too and can often offer you much more bang for your buck.
Did the lock I put on my door actually prevent anyone from breaking in if nobody ever tried?
In my mind, regardless of your license, you still have to be able to defend your rights, or you don't really have any.