I always pull my gun on them if Im stopping for them. Dont put it DIRECTLY on then, cause they will freak, just put it to their side. And kinda move away a bit once you trigger them to start talking. That way you make some distance.

Honestly, when I played through it, the vast majority were just people needing help. I had maybe 3 people try something the whole game, and one guy actually took my horse. I was in the mountains and he jumped on it, and ran right off a cliff.