Many hotels overseas have rooms that have a maximum occupancy of two people (two twins beds or one queen bed or one king bed). If the room is large enough, those rooms may accommodate ONE extra bed (crib or rollaway). Fire codes in many countries prohibit occupancy by more than the allowable maximum number of occupants (so either two or three). If you just turn up with four people, they can refuse you a room or make you buy a second room at the rack rate. Very few chains overseas have double double rooms (or double queen rooms). I can't say that Hilton has more double doubles than SPG/Marriott or Hyatt or Radisson but maybe they do.

Whenever we have tried to book four in a room, it has always been a problem, but that would be true of paid rates as well. On the other hand, I do know that at some international properties, a double double (or a family room to use Radisson's terminology) is not a standard room and often costs $20-50 more than a queen. Maybe that's how they get around offering a double double as an award room even if they have them for sale. Can you get a double double for cash but not for points at the hotel you are looking at in Cabo? There are plenty of threads on this subject in the various forums; again, the bottom line is that in many places it's a fire code violation and turning up with four people for a room where the max. occupancy is three is not a good idea.