How many times do you go out on a charter where they don't have you pay up front, or at the very least leave a credit card number. So, I'll say it again, I had paid in full already. I owed the shop nothing. I rented nothing. There was no reason for them to want to keep the card. They could not give me a reason for needing to keep the card. Another person who going to go out on the same boat did not have his card at all and they accepted that another shop was holding it. So they were allowing someone to dive off one of their vessels without showing any card at all.
And on top of all this you are telling me, as if justifing it, they are holding the card hostage in the hope of receiving a tip. Any tip should be between me and the crew of the boat. So from now on I will be justified in requiring them to allow me to hold their drivers licence, to make sure that they don't drive home that night without returning my card.
But I do realize that you are probably right. This is their way (policy) to make sure that I will come back into the shop. Yep, this is the type of business I want to trust. So on top of all this, and to keep this tread on track, I'm going to show them let alone allow them to hold an instructor or dive master card?