B2S, The idea is only really taking the court pleading system to the football pitch. IE you rely upon the integrity of the player to say 'guilty as charged' or 'not guilty'. The point being is that you then punish the player far more if they plead not guilty and force the 'trial' and they are then judged to be 'guilty'. However, as in all walks of life the drawback is 'intent'. Hanball being a particularly awkward bit of legislation as it has to be 'hand to ball' - ie with some form of intent. I personally think in Henry's case, the first contact was unintentional - so that wouldn't have been punished - but the second touch showed (IMHO) intent.
The problem will still be the play who jumps or slides in and their hand is then in an 'abnormal' position and the ball strikes it (that then isn't necessarily handball) BUT you could argue that you assumed that body position to create a bigger obstical - so therefore was intentional.