In the aftermath of the match, Cats coach Chris Scott described the decision as a "horrible error," while his counterpart Alastair Clarkson admitted he would not have liked to win the game with the interchange steward's help.
The incident could have been pivotal, given it happened in the midst of the Hawks' final quarter comeback, gifting a goal to David Hale to draw them within nine points.
AFL football operations boss Mark Evans spoke with Scott and Cats officials in the rooms after the game to confirm the free kick and automatic 50-metre penalty against Josh Hunt for the infringement should not have been paid.
Only Geelong's ability to steady and close the game out saved further embarrassment.
Both Scott and Clarkson called for the rule to be softened.
"I'd prefer it wasn't so harsh," Clarkson said.
"It's such a combative game, and there's so much going on, it would be great if they could come up with a [lesser] penalty.
"There needs to be a two-metre buffer or something, in terms of getting on the ground – don't worry about it.
"I would have loved to have won tonight, but I would have hated to have won it based on a mistake.
"The League should look at it, because it's a harsh penalty for what is a pretty honest mistake ... sometimes by a volunteer interchange steward."
Scott expressed his relief that the decision did not cost his team the match.
"The bottom line is, I think the rule is a poor rule, especially when a mistake is made," Scott said.
"A goal had been kicked. There was time to double check it, maybe even triple check as well.
"It's a horrible error, but it didn't cost us the game. So all's well that ends well."
The rule was created following a 2008 match between the Sydney Swans and North Melbourne, during which the Swans briefly had 19 players on the field.
Ben Guthrie and Mark Macgugan are reporters for AFL Media. Follow them on Twitter: @AFL_BenGuthrie and @AFL_MarkM
