Firstly bad luck to all involved, would like to echo WWW sentiments that it is refreshing to see a buisness that has gone under behave in an decent way to its patrons.
I doubt the risk is any less with big schools than it is with small schools I imagine big schools have huge debts to service, large staff bills etc etc whilst the smaller school maybe able to cope with lower costs but has a smaller cash flow..
I certainly would not be paying upfront for a CTC/OAA course at the moment, or ever in fact...imagine if they went how many people would be seriously stung.
Do not pay up front, always use a credit card.