Regardless of if the system lets this behavior occur or not, it goes against what the system says it should do. So ultimately, a user that was honorable would have said, "hey Rob, this is not working as you intended it to".
I think the real solution is for PoDC payments to work like this:
PoDCUpdate looks and sees what you need for stake given your RAC
PoDCUpdate does a transaction going for 110% of the necessary stake
The Transaction becomes locked
The next time PoDCUpdate runs, it checks if the locked transaction exceeds the minimum required for your RAC, if so, no new transaction, if not, it does a new transaction
When the Payment is triggered, it ensures that all transactions for stake are still locked (much like with a MN payout).