I noticed that the spacing in the corner where failure occurred appeared to be much less than at the top. (IOW, the glass didn't look "square" in the case.) However, I figured that could be attributed to parallax in the photo.
Aside from "duct-taping" the glass around all sides for shipping, (or adding an adhesive bonding agent) I don't see how you could guarantee that big glass slab against heavy shocks.
Since I don't have a sample to work with -- or competitors to analyze, I guess my solution would be to label (in all appropriate languages) the packaging with:
"DANGER! NITROGLYCERINE -- DO NOT DROP OR JOLT PACKAGE!!!"
'-)
They could squeeze some shock-absorbing material in that tiny space between the glass and the frame, with a “remove before use” tab on it.