The consensus is a hotel can have up to 3 (not 50) PL rates. It is not clear if the hotel is allowed to keep more than one night in the case of a no-show. With multiple hotels in most zones and up to 3 rates per hotel I wouldn't think Pl would get much money from overbids. I guess someone who used PL posted rates on the bid screen and then just took 20% off the rate might overpay by enough for PL to get some extra money.

A few (old) PL agreements/contracts with the hotels were posted on the web. It's not clear if the policies have changed since.