Well, presumably if OP statement were true, recreational diving would involve large numbers of casualties. Casualties in recreational diving are somewhat rare, however, at 2 per million dives.

Tourist dives are even safer since they do not perform advanced dives. Overall, the evidence does not support the view "If you really have only a vague recollection of basic safety checks you shouldn't be diving - seriously."

Most tourists diving have only that and they're not dying in droves.