Wow, just wow. Not even a Glock will go bang without the trigger being pulled. It just won't happen. Snag on draw? Pulling a pistol from a holster would have all of the forces moving in a direction that would push the trigger forward. Dropped and going bang. That's been well covered. Falling out of the holster? Get a holster that fits. Falling out of your hand? Get a grip

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There are so few accidental discharges that they are beyond statistically significant. Negligent discharges are far more common. Yes, any of us are susceptible. One of the reasons I love carrying my XD 9sc is that it has some bulk to it. I know it is there and I am not completely comfortable when it is on my waist. I am reminded that I have a tool which is capable of destroying a life, mine of someone else. It stays in the holster. I remove it when I go to the range to practice and when I clean it. I take the holster off my belt, the pistol stays put. Keeping you head, and your hands where they are supposed to be make it possible to safely carry a loaded firearm.
Every Marine knows that the only reliable safety for a firearm is the one between your ears. If it fails someone is going to get hurt.
Carry on!