I don't mind being "ignorant"...
- Diving without a recent medical (IE undiagnosed health issues)
- Violation of training guidelines
- Failure to maintain sufficient breathing gas reserves for the dive
- Solo Diving
- Diving > 100ft END
- Failure to maintain a continuous guideline to the surface.
- Improper gear for the dive
These are just as ignorant and meaningless as the original guidelines.
Who's training guidelines? (rhetorical)
Who sets the arbitrary limit of 100ft END? There are divers I would not think twice about diving to 150' on air in a cave with, and some I wouldn't go past 70' on air... so what? Where is your ppO2 rule? How about CO?
Rather than putting diving solo on the list, how about "Diving with an idiot"? That rules a lot of people out from solo dives... and look how many of your "solo deaths" are now ruled out...
Who decides what is "proper" gear? Anything with a "H" on it?
Here is my take:
Exit - A known, personally and recently verified, unambiguous route to fresh air, followable without the use of sight.
Reserves - Enough gas to get you out despite major gear failure AND significant delay.
Redundancy - Buoyancy, lights, gas supplies, etc. Quantity depends on reliability and consequence. (this covers Solo diving)
Knowledge - Know the dive plan. Know everything needed to complete the dive. Know every knowable contingency.
Experience - Have experience in planning similar dives. Have experience in completing similar dives. Have experience (even if simulated) dealing with knowable contingencies.
Competence - Be able to easily perform the skills required to complete the planned dive and knowable contingencies.
Gas - Appropriate for depth (O2, N2, He, CO, CO2).