Years ago I found some advice online about attaching a strap to a camera that makes it virtually impossible for the strap to come off, I have been attaching my camera straps this way for at least six years and I wouldn't dream of doing it any different. I had to reattach a strap to one of my cameras because Canon repair prefers if you remove any accessories when you send gear in for repair, and I figured it was a good time to share this technique. I prefer the Domke Gripper strap because they are small, grippy, don't get tangled, and have a simple design. This technique should work with any strap that has an adjustable plastic buckle.
First unravel the end of the strap. The Domke straps have two rubbery keeper loops and an adjustable plastic buckle.
Pass the end of the strap through your camera's eyelet, then through the keeper loop.
Then pass the end of the strap through the buckle as normal.
Next the end of the strap can (optionally) go through the keeper loop on the inside of the strap.
In the next step we thread the strap end back through both parts of the buckle. This is what secures the strap and keeps it from working itself loose.
Next is what I consider to be double insurance. It's a bit tricky, but if you hold down the end of the strap with your thumb, you should be able to force the rubber keeper loop toward the buckle and over the strap end.
Et voilà! This strap will not work itself loose.