Thought I'd share this... A few months ago I finally got tired of the neck strap that came with my 6D and bought a sling strap. I love it, and it's very comfortable, but when I bought it I read a couple reviews about the screw working loose from the camera screw mount, with the warning to always use a backup tether. I bought a tether with the strap, but didn't put it on right away; and didn't have any trouble with the strap unscrewing from the camera mount. A couple weeks ago my wife & I did the Kelby WW Photowalk. As I was getting my gear put together I came across the tether - still in it's package. For some reason I went ahead and attached it to the camera & sling. At on point on the photowalk I felt my camera at my leg instead of my hip as normal. I reached down, and realized the camera had come loose from the sling and was hanging from the tether. I reattached it, and no harm done; but the thought that the camera and 100mm macro lens could've hit the pavement & been lost was a sobering one. I'll never go without a tether again, and will make it a habit to occasionally check the mount to make sure it's tight.