Which can be easily deleted before posting. And now in post # 24 we learn there actually were no cabins assigned. Like I said, speculation is pointless. Good luck.
I can't help but notice the line that says "Rewarding Exceptional Service: Additional Gratuity". (emphasis mine)
Justify it however you like, but the purpose of this form is NOT to abbrogate or alter one's $16/day responsibility.
We used them many years ago (15+, son got bit by a monkey at an iguana farm---had to get rabies shots when we returned!) but booked thru Shore Excursions Group this time.