i dont agree with this because of 
if he sees the shaco coming and predicts his attack, he should have the ability to outplay him by activating counterstrike. and what about invincibility mechanics?
i think well timed defensive steroids should allow to negate shacos backstab damage and break his invisibility at the same time. otherwise he could have the option of turning around and walking away still invisible, when he realizes the attack didnt connect. makes him too forgiving in these scenarios.
if you cancel an auto attack on shaco or not, is entirely in the hands of the shaco player. just dont make that mistake.