Greeks were probably babied by the University admin handling tailgating for them in the past, and after all the hoop-la over the last few years of University admin clamping down on student tailgating, athletics took over. This changing of the process (for the better long-term) is probably why the Greeks missed out on reserving their spots. (Not so tough) lesson in responsibility.
That said, we need our Greeks at the games so hopefully something can be worked out.