Only because nobody was hurt do I find this amusing...
Given the number of people who are probably on staff with that show that dabble in 'physics', you'd think they would have considered the backstop for something like this.
Also, isn't there something somewhere that says something to the effect of 'be sure of your target and beyond'? I recall reading that somewhere...
I would totally be ebaying anything that cannonball hit though.
Wiley.