Indicators that you might be in a posh marina

Directions to the washrooms are given as "Down the hall, then turn right down the short corridor and it's the first door on your left" instead of "Just down the hall here and take your first right" trusting that you know whether you should go into the little girls room or the little boys room.

The second indicator... there is a powder room separate from the actual washrooms.

And the clincher. Oh yeah, I totally used the mouthwash (there were even individual use little plastic cups!)