Safe operation of the system includes very positive methods of insuring that the gun does not discharge when being holstered. Some of them are holding the hammer down when holstering a revolver, holding the hammer back when holstering a cocked-and-locked autolader, holding the finger behind the trigger when holstering some pistols. This may not be possible with all pistols and all holsters, especially certain striker-fired pistols, and certain covered-trigger-guard holsters.
Not every combination is safe. The owner is responsible for figuring out which. A good start might be not to buy a striker-fired pistol, although this is certainly not a hard and fast rule. There may, in fact, be some circumstances which call for the appropriately-ridiculed Israeli carry, although IMO it would usually be wiser to carry a different gun, even if you have to buy one.
"Darwinism" may work fairly well for appendix carry, but only for the younger.