I did the cave tubing during the time Carnival was not offering it and was completely satisfied with Major Tom. I have not personally heard of anyone dissatisfied with Yhonny. Whichever one of the three you choose it is the same tubing ride. The only difference will be the guides and which bus you ride. This is a must do excursion.
Hubby and older son did it with Yhony (cave-tubing.com) and had a blast.
I, too, have been reading the Belize board for years and have never heard of Yhony or Major Tom missing the ship.
Although it "could" happen, I believe they understand "getting back to the ship on time" is the basis for their business.....
COMPLETES THE FLEET
If it is Carnival and it floats....we have sailed it!
Hubby ... DIAMOND (every ship except the Carnivale)
Me ... DIAMOND (every ship starting with the Tropicale)
20 year old son ... DIAMOND (every ship starting with the Tropicale...he is the only DOUBLE Milestone under the age of 21)
24 year old son ... DIAMOND