I still think examples like this are so unlikely that they aren't really worth considering. No fighter or rogue is going to waste a Shatter on armor when weapons and, most particularly, shields, are much, MUCH better targets. And if a rogue is attacking from behind, that strike would be significantly more effective as a Terminate or an Assassinate. Only a fighter might be tempted to swing a Shatter and that still is a poor use of a skill when just about every other fighter skill (except Disarm) would be better.
Also, while I acknowledge that every game is different, I can't think of even one character that I have ever met that wears a backpack (in over 20 years of play). I've never heard of a backpack being made indestructible. I am certain that one exists somewhere in the game (mostly due to Murphy's Law), but you can't convince me that indestructible backpack wearing characters are suddenly going to become a plague on any game.
-MS