Was it? Is there a dive operator in this thread who has a problem with their existing booking system that needs solving? And is that problem with on-line vetting of the prospective customers?
If the dive op, for example, requires AOW for dive X, and a customer shows up without AOW and demands they take him on dive X, it may be that the op failed to clearly articulate their requirements. That doesn't require a booking system, it just needs a bold font on a webpage. It may also be that the customer is insufficiently trained -- specifically, back in the elementary school, in their reading comprehension skills. A booking system won't help with that. So, what is the actual problem the OP is trying to solve here?
If the dive op, for example, requires AOW for dive X, and a customer shows up without AOW and demands they take him on dive X, it may be that the op failed to clearly articulate their requirements. That doesn't require a booking system, it just needs a bold font on a webpage. It may also be that the customer is insufficiently trained -- specifically, back in the elementary school, in their reading comprehension skills. A booking system won't help with that. So, what is the actual problem the OP is trying to solve here?