I have also been in a cruise directors office when we were going over comment cards (when I was on staff)
As much as I hate to say it, I have to affirm what Bruce just said, the comment card is not the place to go into long detail about something. The only things that get tabulated are the ratings.
As far as grammar - remember people writing on comment cards don't have a spell-check or word processor, or even a typewriter. Its a lot easier to write when you can cut & paste and revise your thoughts without leaving eraser marks.
Cool! I got the NCL bouncy ball ad. I like that thing.