Knock on wood, never have. I did break a piece of plate glass (which was a good thing) by accidentally lifting up a little too much/bending it while taking it out of the game (tempered glass doesn't mind much) to avoid an obstacle, something like the shooter rod of the game across from it. It took a clean chunk out the top right of it with no mess. This was just after I bought the game and was taking the glass off for the first time (or it wouldn't have been that type of glass), and I'm glad it happened so I could replace it with the appropriate glass, tempered glass, and it saved me from any danger or harm down the road. As soon as I found out it was plate glass it would have been replaced (or at least "marked to be replaced") immediately anyways (likely only minutes later), so it made it nice and easy for me at least!

I actually have placed tempered glass playfield sheets and cold concrete out of fairly warm games too with no issues. I usually rest them on the top of my shoes first and then go to the floor. Sorry to those who lost a glass doing nothing but: more than once I've actually blatantly dragged unused sheets of glass across the concrete floor with stick-on tiles on them without them breaking. Pretty sure it actually left marks on the bottoms of the glasses but didn't break them. Yes, they were all tempered. Still have them to this day. They frequently sit on the cold floor without breaking, either.

NOW after this post, I have to knock on wood a trillion times, cross my heart, cross my fingers, etc....