Forced updates *are* applicable in certain situations -- see mattdm's case above -- but only where the user who sits in front of the computer is obliged, or willing, to delegate system administration tasks to the OS supplier. In the Boston University situation, the OS supplier *is* the administrator and vice versa, so there's no ambiguity.
But if we're talking about a supplier like Red Hat or Mandriva effectively becoming the system administrator for 90% of their less-technical users, all bets are off. They don't have the resources to properly run millions of machines without charge or to respond to the cases where automatic updates inconvenience their non-paying users.
OTOH it's something they or similar businesses could take on, maybe profitably, given the right wording in the contract and the right price -- using mandatory automated updates merely to make it possible.
Technical Unix users will take on their own system administrator role whenever they feel like it, whether their network admins or their OS suppliers want them to or not. So you're *not* the subject of this discussion and won't suffer, one way or the other, as long as you choose to run free software :-)