Not once, but twice were Fremantle and Sydney players penalised for rubbing the head of an opponent, and coaches Justin Longmuir and Dean Cox were in agreeance with the umpire's call.

The AFL introduced the rule in Round 3 after Dockers antagonist Patrick Voss was deemed to be taunting Melbourne's Harrison Petty as well as displaying a 'cry-baby ' gesture.

On Thursday, Fremantle defender Luke Ryan was penalised for the act against Swans gun Chad Warner, handing Charlie Curnow one of his five goals in the first term.

Later in the evening, Sydney veteran Dane Rampe met the same scrutiny for rubbing Jye Amiss's head.

"It's clear. The AFL said it's clear. Maybe we could have educated our players a little bit better on that," Longmuir said of Thursday night's hair-rubbing free-kicks.

"I haven't seen it in the game for months, so for two to happen in one night is a bit odd.

"But the AFL has made it really clear that you can't do it. So why do it?"

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Cox was in agreeance.

"You've got to adhere to it and be disciplined in the moment," Cox said.

"Don't let frustration change the outcome of what you should be doing. You should be focusing on what you can do next, not on trying to rub it in a little bit.

"The best teams don't do it. So we need to make sure that we're really disciplined in those moments."

The Swans coach was questioned on Rampe's action, admitting it's more frustrating coming from one of the leaders.

"There'll be slip-ups, but as coaches we are a bit firmer on our leaders than our kids, and so we should be," he said.

But where's the consistency?

On multiple occasions last weekend, headed (excuse the pun) by Richmond's Seth Campbell, players avoided a free kick against for deliberately rubbing the head of opponents.

Campbell gave Carlton midfielder Sam Walsh a good ruffle, with the umpire looking clearly at the contact, and deciding not to blow his whistle.

AFL legend Jason Dunstall can't comprehend how football rule makers can differentiate with minor head contact to genuine sledging and physical contact that aren't deemed as free kicks against.

"You'd like to think the players would get the message," he said.

"It's a rule. If you transgress and get pinged, and we're seeing it cost goals, you're an imbecile. That doesn't mean I like the rule. The fact that we draw the line at, in particular Rampe, just tapping on the head, the fact that costs a shot at goal but you can do whatever you like. Run up and chest someone, sledge the crap out of them, yell in their face, that's okay.

"But a little tap on the head, I don't get it."

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