Several years ago, my wife and I took a 7 day cruise from Seward to Vancouver on Celebrity. We decided to go on a helicopter excursion to a glaicer, but we did not book on the ship. At the time, I was 6'2", 240 pounds -- with my gear on (boots and coat), I was closer to 255 pounds. Since I tipped the scale in excess of 250 pounds, I was assessed a 50% surcharge. As it turned out, I got on the helicopter with a guy from my cruise who was closer to 275 pounds (without his gear). He told me that he was not assessed a surcharge because he had booked on the ship -- This fact was confirmed to me later at the excursion desk.

Not withstanding the unpleasant argument I lost (I offered to go up sans coat and shoes), the helicopter tour was one of the highligts of our trip, and my wife loves to tell the story at parties.