We didn't book ours through Carnival when the kids did parasailing in Cabo, we paid for them right on the docks. And, I was able to go with and watch, it cost $10 for me. When you get on the ship go to the help desk where excursions can be booked and you can ask and do that there. Or call Carnival ask for excursions and ask before hand also. Enjoy yourselves, we loved Cabo!
Happy Cruising!
Kim :-)