I haven't had this back for very long - it's on an Alpa STC. When I first got it I noticed that my right thumb sat against the latch for the back when I held the camera. I made a mental note to stay away from the latch.
Unfortunately my thumb naturally lies against the latch, despite my best efforts. You can see where this is going can't you? I was sitting on a bench to take a photo and received a phone call. I swung to the left and put the camera down on the bench to retrieve the phone from my pocket. As I did so I depressed the latch the the back gracefully fell backwards off the camera onto the bench. I hardly knew what had happened. I'm still recovering from the palpitations however.
So I've now done what I should have done in the first place. Given that I remove the back and the adaptor together most of the time I don't need the latch in daily use so it now sports a cable tie on the shaft of the latch. It can't be actuated without removing the cable tie - cutting it off. The picture below shows in blurred iPhone fashion how it works. It also shows all of the dust that you never see in daily use :-)