My recent experience is exactly the opposite. I had booked a reservation under my name for a trip with a friend. However, due to schedule changes, my friend was expected to arrive at the hotel several hours before I was.

I called the hotel to have their name added to the reservation, and they said "No way - it's a Priceline stay and we don't have to". (other than that, the Chicago Sheraton staff was friendly)

I called Priceline, and they called the hotel on my behalf and added the name. They even called me back to confirm that it had been done - nice touch. Perhaps my dozen Priceline stays in the past 3 months helped...