Matt, I think you have this totally backwards. First, it doesn't matter that the damages were voted on and passed. If it did no court would ever invalidate any liquidated damages clause because it is, by definition, a part of a negotiated contract. So the next question is: at the time of signing, or at the time of breach, are the damages reasonable? The damages don't relate to the breaching party (Maryland) but to the non-breaching party (ACC). Taking the question at the time of breach it is pretty clear the damages are not reasonable. There are/were a number of reasonable alternatives (e.g. UConn / L'Ville) available as replacements, the TV contract wasn't impacted and there are no scheduling impacts.
The harder question is were the damages reasonable at the time of signing. By all accounts this was a last ditch effort to hold the conference together so that reaks of punitive damages, despite calling it a liquidated damages clause. Moreover, the environment at the time showed a number of schools expressing interest in the league (too many to list). The question the ACC will have to answer is what changed in September of 2012 to warrant increasing the damages clause by $30M? The inclusion of ND? Shouldn't that help to mitigate the damages?
I also question the fact that many people see this as a litmus test. One could argue that regardless of what fee Maryland negotiates the next departing party will have caused irreparable harm to the league and the $50M will become effective (e.g. who is an appropriate replacement for FSU?). It will be interesting to see how this plays out, but I can't see Maryland paying much more than the original fee, so lets say $22-$25M.