Re: This MUST have come up before, but...
I'd interpreted the quantum locking as meaning that just as they can't move if you're looking at them, as the act of observation prevents them changing state, that extends to other changes of state, such as being damaged.
So you can't smash them if you're looking at them. You could try smashing one while looking away, but if you do that, it can move and get you.
"Some days are better than others. They say that where I come from."
"Loudly, I imagine, on the day you left."
(Blake's 7 - Rumours of Death)