Quantum grounds are very tricky: they are both safety earth bonded and simultaneously not safety earth bonded.
Once you open the chassis and observe the ground, then it will actually be bonded or not. So long as the chassis is not opened, you are always simultaneously safe and not safe.
Often people think that they can just use the equipment with the chassis opened and they can be sure they are safe...but this isn't true, because when you look away to change the EQ, the safety bond goes away and doesn't go away.
Like the concept of simple addition to a drummer, it's neigh incomprehensible.