Hawthorn, who won a thriller by five points, scored a crucial goal after the siren at three-quarter time after Jack was controversially ruled to have entered the protected zone of Hawk Jonathan O'Rourke.

O'Rourke was brought within goal-scoring range with just five seconds left on the clock.

Under the so-called "east-west" rule introduced at the start of this season, opposition players are not allowed in a corridor five metres either side of the mark as well as a five-metre radius behind the player with the ball.

The ruling was arguably the most contentious decision on a night where the performance of the umpires was a major talking point.

Michael Christian, who is on the AFL's laws committee, described the call by umpire Shaun Ryan as a "bad error".

Christian, a former Collingwood premiership player, believed Jack was already in the protected zone when O'Rourke marked and had made sufficient effort to leave.

"You have to get out of the area immediately but you don't have to run sideways nor on an angle," Christian said on radio station RSN Racing and Sport on Friday morning.

"The rule is designed if you're outside the protected zone and you run into the protected zone, 50 straight away.

"But when you're already in there you've got to give time to the player to run out. I think it was a mistake by the umpire because he was already in there, he ran out immediately, he didn't sprint but he was going quickly enough to get out of the area, realised he was in there and the whistle blew. Bad error, I reckon."

Hawthorn scored a second goal from a 50-metre penalty in the final quarter after Ben McGlynn was deemed to have incorrectly stood the mark.

Swans coach John Longmire said after the game he was unsure if the interpretation of the rule had changed but indicated he will not seek an explanation from the AFL's umpires department.

I don't know, ask the umpires," Longmire said. "I don't know, I really don't know to be honest."

There has also been much discussion over a lop-sided free kick count which went against the Swans. Hawthorn received 15 free kicks to Sydney's nine though the tally was a heavily in the Hawks' favour 13-3 at three-quarter time.

"Obviously we were undisciplined because I don't think I've seen a differential like that for quite a while," Longmire said.

"I'll have to go back and we'll have to get better at our discipline clearly, because that's a big differential."

AFL chief executive Gillon McLachlan said he believed the penalties were "both clearly there".

"I don't think anyone's disputing the 50s were there," McLachlan told 3AW.