Quoted from wesman:
I'm sure there's a reason, that's been elaborated on before, but aren't there possible glass substitutes out there to use for pinball?
I bought a Demolition Man that came with plexiglass cut to fit. It offered minimal security, had a bit of sag, and the flippers, of course, were much louder. Maybe halfway between glass and no glass. Additionally I had some shards of plate glass to remove from the right ramp when I bought the game. Fortunately minimal damage to the machine in whole. Thinking back I can't understand what type of environment that was in to cause an urgent need for plate glass (HUGE no no in so many ways on a pinball) let alone having that replaced again. During my operating days games usually had break ins via the coin door not the glass. There wasn't any lock bar damage unless that was also replaced.
If you are really concerned about glass breakage I'd get that safety film and put it on both sides of your tempered glass. Even then no promises to what damage you might see.