What Are the Odds?!?

I got in to work this morning and found that overnight, one of my tanks
bottom glass "gave out".

I didnt realise what had happened right away...

I had assumed that the bottom seal gave out so naturally I took everything
out and was going to re-seal the tank.

I was amazed when I got to the bottom and saw the tempered glass was
shattered!

Has this happened to anyone else before?

~Mort