And you're right, Cruise Planners/American Express Travel is one of the largest consortiums in the world. In fact, Entrepreneur magazine ranked us the #1 cruise only agency for 11 years in a row!
But as for Regent and group rates, alot of agents were doing something not quite kosher and causing problems. They would have a client who wanted one cabin, so the agent would create a false group, sell one cabin to the client, and then cancel the rest of the cabins. This would take 7 cabins out of circulation for others to sell until they were released and then they would use the group amenities to give to their client even though they never had any intention of selling the rest of the cabins. This was creating major problems for both Regent and for those wanting to actually book a honest group of cabins. I won't go into a long dissertation as to all the problems this was causing, but it was a dirty little secret among those 'luxury' agents who like to dishonestly manipulate the system for their own benefit while not caring about the problems they were creating for everyone else.
Cruise Planners/American Express Travel pre-books well over 40,000 cabins in group space every year and unlike some of these other companies, we take it very seriously, which is one of the reasons why we are so highly respected in the industry and have received numerous prestigious awards and accolades year after year.