Have to say it's pretty disillusioning seeing this new rule in action. I am unconvinced that this alleged deliberate cheating by defenders has become so sophisticated and widespread that it needed the rule to be changed to such an extent.
In a highly physical, mobile game like football where things are happening at lightning speed it's just not possible for a defending player to foresee situations whereby a ball might make contact with an arm that isn't locked down by their side, nor is it even possible to change your arm position most of the time. As Ella in the pod says, "it's literally physics!".