I had them fall off in the past, with Fender-style buttons, which are horrible.
Also had a problem with the screw working itself out when I used those rubber washers.
Haven't had a problem at all since using the over-sized strap buttons.
It's probably not as much of a concern if you don't gig - just sayin'... IME, live performances definitely increase the chances of a strap coming loose as opposed to rehearsals or playing at home...