Nearly every front rower leads with their shoulders, or at the very least stands upright to take an opponent front on, but that is a side issue.
The rule states that any initial contact with the head can result in a charge. It's a pandora's box, that even you now have begun to interperet, you said now it's a case of "reasonable care"? How do you judge/grade reasonable care?
If a bloke hangs his arm out resulting in initial contact with the head, I don't have a problem with them being charged. And no you stupid dog fans, Morley's initial contact was with Cat Utai's shoulder last year, not his fat head. But if a fdefender stands upright to take a runner ball and all or to put a hit on, and through no intent intially contacts the head, then yes, I have a problem with that because you cannot judge/grade/interperet intent.
Chook.