Thank you! That was exactly what I was thinking, but you beat me to the post! And yes folks, a lot of modern windows ARE made of tempered glass, especially the large ones used in commercial buildings. Why? Strength for one, but more importantly, LIABILITY CONCERNS when the glass gets broken.
You also don't generally have the opportunity to put part of your body weight in a downward fashion on a window, picture frame, etc. like you might if you happen to rest your elbows on a playfield glass, or if one of your kids jumps up on top of your pins while you're not looking (if you think this won't happen you don't have kids), etc. If you think plate glass in a window isn't potentially dangerous, go lean all your body weight up against one so you break through it, and see if you're lucky enough to not get seriously cut in the process.
And I never claimed tempered glass doesn't break - I absolutely said it can break easily if hit at the edges. Good thing all edges are completely concealed and protected when it's in a pinball machine. It can take an amazing amount of abuse on the flat surfaces, which is why it is used in this application. And when it does break, it's in a huge number of tiny pieces which cannot make anything more than annoying small cuts if you were to come into contact with them.
As far as plate glass use in games from 1977-back, does it not occur to you that the change came into play EXACTLY at the transition period from EM to solid state...that higher powered flippers and faster playing games in the solid state era require this level of safety?
You should go back to answering questions on monitors and what have you, and leave the pinball playfield glass questions alone. Your head is buried deep in the sand and your unwillingness to listen to reason and experience is of epic ignorance...and those that blindly follow you are equally ignorant.
Seriously, the "advice" you have offered here is some of the worst I have ever seen. It's sort of the pinball equivalent of telling people to run old style monitors without an isolation transformer, it's OK to plug your 100V Sanyo into your house wall socket, and there's no reason to power down the monitor before removing the high tension line from the tube...
Richard