I propose the following
Anybody who wants to freeze their head for the purpose of returning to life later, has a brain not worth freezing.
Proof of this is beyond the scope of this essay, but should be bleeding obvious to everyone with a brain worth freezing.
Corollary 1: All brains worth freezing will only be frozen for the above purpose against the will of the owner of said brain.
Corollary 2:Freezing of brains for the above purpose is either (i) a waste of space/time/energy, or (ii) evil
Of course, if you want to freeze your head for the purpose of scaring the willies out of your descendants, that is an entirely different matter