That's AC/AP's entire problem -- they have this absurd view that if they deny someone an award seat, then that person will pay cash to buy the same seat. They even have a backup plan in case that person doesn't actualy fork out the cash -- they'll sell the seat to someone else.

Much like upgrades -- if we make them harder to get, people will instead buy a business class ticket.

I guess it just gives them a warm and fuzzy feeling, much like that described in an old Monty Python song.