The takeaway: In the hotel and rent-a-car businesses, because the thing being rented is so valuable compared to the rental fee, hotels and RACs risk having their rooms/cars damaged/dinged/beer spilled in them. Conversely, guests of hotels, and auto renters, risk bogus charges on their CC bill. Both camps have stories to tell. But no one here has offered even anecdotal evidence that people who purchase lodging or travel through PL are more likely to damage property than are users of other distribution channels.
Priceline only requires $100 hotel deposit by credit or debit card, or $200 for cars. Some RACs require you to show a return ticket to use a debit card. Hotels have the right to not accept debit cards for incidentals, but I have never heard of this happening. Usually the hotel just charges the amount of the incidental deposit to the debit card and refunds it later.
Priceline hotels are not allowed to charge or authorize a $250 deposit to ensure against beer-keg-blasts or non-smoking-room smokers.
And as far as extending another night while on a PL reservation? Cannot be done.
Bzzt! You can often extend your Priceline stay, at the same price, and usually an extension can be requested until 11:30 AM the day of your scheduled departure.