A recent event at my house I thought would be interesting to share.
MY dog was using her very aggressive bark, usually reserved for javelina.
I went out to see, the dog runs to the edge of the dry wash, I follow expecting to see some wild life and I did!

 

The kids that are recruited for mules typically don't carry firearms. Not to say it doesn't happen. I've never seen it, but I'm not going to confront them either. The G.F. was doing the video shoot.
The Border Patrol is already a little quick to pull the trigger (sadly, even on themselves) and the mules knows this and are only trying to avoid detection. As armed resistance would only mean a fire fight with guys with m-4's. I'll let you do the math on hand gun vs rifle.
The dusting is for B.P. detection. The B.P. routinely does slow drives looking for prints at the edges of the road. I guess they thought that there would be a chance that their passage would go unreported.
I don't go hiking without protection. But not for snakes as the encounters I've had with them were over before I could have gotten it out of the holster. Besides, I'm not into killing snakes in the wild. I'm more concerned about rabid animals, or zombies.