What happens if you get behind

I'm just contingency planning here. Does anyone know the protocol most schools have if you get behind on rotations for whatever reason? Say May of your graduation year comes along and you still have one, two, or three more rotations to do before you complete the requirements for graduation. I know this screws up your ability to start residency, but is the school obligated to confer the degree upon you once you have completed the requirements, or can they (and do they) withhold conferring the degree until the following graduation date? My assumption is that you get the degree, it goes on your transcript, and you just walk the next year.

Having said that, what happens as far as residency goes? Do you flip burgers for a year until you can match?