A pair of helmet fouls involving Ito Smith show how prevalent it can be

And the penalties reveal how prevalent the fouls will be, if the rules are enforced as written.
On a kickoff return following a Jets touchdown, New York cornerback Buster Skrine braced to tackle Falcons running back Ito Smith, who was returning the kick.
Smith likewise braced for impact, with both players dropping their helmets, instinctively.
Skrine, who was injured due to the impact, received a 15-yard penalty for lowering the head to initiate contact.
Smith got a flag of his own, a few plays later.
While attempting to make a block in the open field, Smith dropped his helmet and made what appeared to be incidental contact with his helmet to the midsection of a Jets defender.
The officials flagged Smith for lowering his head to initiate contact.
The players in question lowered the helmets to initiate contact and they made contact.
In neither case was the blow forcible or punishing or otherwise indicative of an intent to use the helmet as a weapon.
But that doesn’t matter, because the rules contain no such requirements.