If you are late, and miss the private tour ... private trip insurance generally WILL NOT cover you because you were at Cabana's too long (not even Disney covers you for that). If the tour operator does not show up, or does not fulfill their end of the bargain, there is no guarantee you will get a refund through private insurance. Typically, insurance companies want confirmation. Try getting confirmation from an operator who did not cooperate with the guest.
I have heard many people use Captain Marvins - usually it is good feedback. That aside, of all ports to exercise caution ... Grand Cayman (or ANY port which tenders) is one you do not want to risk being late. Saving $10 sounds good, but if you are 2 minutes late ... you just spent THOUSANDS OF DOLLARS to save ten!
Steven
If you prepay for a private tour and the ship doesn't make it to port - your private trip insurance (not DCL's) generally WILL cover that cost - if the vendor doesn't offer a refund. Trip insurance may or may not cover the cost of an excursion where the tour operator doesn't show up. (That tour operator may not be in business long, either!) As sayhello said - appealing to your credit card company to dispute the charge may be sufficient. However, trip insurance doesn't cover stupidity - like missing a tour (or the ship) because you weren't paying attention to the time - for whatever reason.
In 2005 I used Native Way Watersports for an excellent Stingray and Island tour in Grand Cayman: http://www.nativewaywatersports.com/. That tour was in the middle of the day, with plenty of time before and after to get off and on the ship. I would have no problem booking with them again.
