Pilotbear, your analogy doesn't really work. A house has value hence the bank's willingness to pay up front on your behalf. Half an ATPL course has no value.
Which bit are some of you guys not getting? If someone wants significant cash up front (either the whole lot or by installment) they have a cash flow problem. It doesn't take much for that pack of cards to collapse. The principle is not unique to PTC or the aviation industry, it applies across the board.