I think a lot of Regent and Silversea guests are trying the new larger Seabourn ships that would not have liked the triplets. Those that are triplet fans may not like a larger ship. The size of the ship does change a cruise and we all like different things.
This probably accounts for all the first time Seabourn guests. Seabourn will have to pick up a lot of new guests to fill these larger ships and they wont all be from the loyal Seabourn triplet fans.
