The irony is that a thief will likely pick that rock up and throw it through the window. Think about it, it's the best way to be a successful burglar. If alarm goes off or dogs start to bark you run and get away, if nothing happens after smashing a window, it's likely safe to sneak inside.
Only with this rock it'll fall apart and the burglar finds the key ;-)
Only with this rock it'll fall apart and the burglar finds the key ;-)