I found Seabourn to be the best in this area. They never make announcements or put flyers under your door. If you want anything you have to go to the concierge and ask for it.
It actually got to the point where I found it a bit inconvenient to find out certain things. I completely missed the captain's special dinner because it hardly even mentioned in the daily program.
If you are looking for this style of private cruising, I think Seabourn is your cup of tea.