Actually it does work for everyone.

They offer trips on ships that are not full in a better suite or for a longer cruise. If necessary cash back or a larger future cruise credit.

The ship they are bumping from is FULL and the ship that the guests bump to in the offer needed extra guests. The $$ amount paid by the bumped guest is retained and may never have come to the company if they had not oversold as they may not have booked a different cruise. It is simply now allocated to a ship where they needed that extra passenger load. Now and then it is an Future Cruise Credit and then at times a CASH offer but that is at the very end and does not happen that much as people take the bumps before it gets to that stage. Overall still a big win for Regent.

The guests only take the bump if they find it advantageous and are then happy about the situation.

It is a win win for everyone. I am surprised more cruise lines do offer the same situation.