So as a DVC member you're penalized if you try to make a last minute reservation.?
timeshares like DVC sell enough pts so that everyone can book a room.
to simplify the situation, assume that DVC is one villa and 12 owners own enough pts for 1 month each. if no one books the months of january and february and 5 of the owners want to book november and december, guess what happens to the owners who wait to book?
someone will be penalized by not being able to use their pts.
in a point-based timeshare, you are better off booking as early as possible to make sure there is still availability. if not, you may be penalized if there is not much left over when you call. the DVC salespeople/"guides" might talk as if you can book whatever you want, but you would be wise to think more competitively.
if one of the owners trades his month for a
disney cruise, then DVC would need to rent his month for cash in order to pay the cruise division for the trade. DVC might use his pts to book the month of june and rent that out for cash...so if you wanted the month of june, you'd be out of luck and frustrated that a cash renter could get in while you could not on pts. but in reality, you are in the same situation as if that owner had used their pts to book june himself.
cash inventory could also come from DVC using pts that they own (they hold some back to use for maintenance if needed, as well as pts they ROFR or foreclose on). but in either case, you are competing with someone else using their pts.