This is the end pin and jack socket on a Cort electro-acoustic.
With a standard Ernie Ball strap on.
This is the problem - the strap can so easily fall off, which it does almost every time every time someone has finished playing and takes the guitar off. When a cable is plugged in it stops the strap from completely falling off.
The reason for the problem is that the flange on the end pin is not large enough.
If it was an ordinary end pin I would replace it but it is the jack socket for the electro workings so I cannot. I have thought about trying to find a large plastic washer, something I could cut through on one side so that I could get it on between the strap and the small flange and then glue the join closed.
What can you practical people suggest?