Tim, I can tell you that I have just gone through that exact kind of situation this week, and while no one from Regent initiated the re-pricing from the higher rate at which I originally booked to the lower current market rate, when I brought the price change to their attention, they did re-price my itinerary, saving me thousands of dollars.
I can't speak for either their formal policy, or their consistency on this issue however, but I'm very satisfied with their response.
Cheers,
Ken
