If I understand what you're asking, not too much. Some people do an even more extreme version of this this intentionally and it's called "walking" a reservation.
The main thing that would prevent someone from doing this is you need the points. In your case, you need the points for your April 13th vacation, and the nights of the 11 and 12th. If you need to borrow points to make that happen, they may get stuck in this use year. Or you may not have the points at all.