Quoted from PoBoyPinball:Don't leave back glass out on top of machine (in garage) even when on a towel and go inside and eat. Put it back in back box or put it some place safe. I did this once only once and my neighbors dogs came in my garage and pulled on the towel you can guess what happened from there it wasn't good.
Damn. There would be some serious hell to pay if my neighbors' dogs came into my garage and destroyed a backglass.