2 times I've stopped an altercation from happening by reaching for my gun (1 time I didn't actually have it, it was just a reflex to grab it)
both stopped in their tracks. One wanted to start something and the other had every intention of trying to rob me
Also since my boss took over the store, we've had zero robberies and thefts. A typical year is maybe 5 or 6. The difference is that my new boss pulled a rifle on one of the local loudmouths making threats and word got around.
Nobody robs a store when you know you're going to get sprayed