Diving seems like one of the recreational activities where it is easy to end up doing something much riskier than you intended (another I'd say is alpine hiking): 1. Being able to easily sign up for a dive at an all-inclusive resort makes it seem more 'fine', you get a false sense of security that you will be taken care of. 2. Dive shops tend to be fairly relaxed with checking if someone is properly qualified to go o…
I've also bought my own equipment because of that - who knows just how well the regulators, dive computers and BCDs are maintained in those places. It's scary enough that you need to trust them with air and tank quality.