As I travel specifically for photography, I'm very conscious of camera security while in a 3rd world country or anywhere a "snatch and grab"
could be likely.
Here's the rig I made up and use to totally prevent the snatch n' grab.
The rig is a 1/16" braided steel cable about 24" long that attaches to the camera with a tripod screw (available at good camera shops) and the other end of the cable attaches to a caribiner which is attached to my leather belt or pack shoulder strap. You want it attached to something very strong. Do NOT use the fabric belt loop on your pants as in a snatch, it would just rip away. The object is to prevent the camera going anywhere.
Now the length of the cable was made to fit my waist to eye-level shooting height and you'd have to make it to whatever length you want to fit your body style. One other great advantage of this system is that should the camera get dropped, with the cable length I use, the camera comes to a stop about 6" above the ground. No broken camera even if dropped.
In use, the cable is virtually invisible and no hindrance at all to shooting. If some kid or punk snatches the camera and is running, he'll get about one step away from me and the cable would come up tight. Odds are he'd be so surprised the camera would pull right out of HIS hands and swing back to me. But he's still running away from me. However, if it was an armed robbery (as happened to me in Cartagena Columbia), unclip the camera and let it GO!!!
But for the average opportunistic snatch and grab, this will totally prevent it.
Note that the cable is from Home Depot along with the crimp connectors (I used two on each end for added security) and some shrink wrap to keep the whole thing neat. Took about 15 minutes to put together.