Some people are "known disasters" and have a hard time finding others to dive with due to their inattention of their surroundings. I don't think it would be feasible to deny them access to the caves (or anywhere for that matter), because they have the card that allows them the access. Unfortunately, there are some people who just don't pay attention to what they're doing and aren't even aware of the damage they impart on the sites they dive. I know a few divers I won't dive with because of their lack of concern and/or inability to watch where they and their equipment are at all times. It's sad that there are people like this who dive. It would be nice if they'd hang up their regs and take up golf or some other land sport.