Shields take minimal work really. The strap that goes around the forearm is put at a length that when the hand is settled into the grip of the shield it's like cementing the ####er to your arm. Then instinctive arm movements move your shield. It takes far FAR more concetration to use an instrument. It's actually pretty hard to take off a real shield. I can see why the instrument would fall way easier, depending on type. I could see this as a way to intruduce some instruments that can't be made to be dropped, via a strap or what have you.