TORONTO -- A viral video showing a dispute over reclining an airplane seat has prompted bitter arguments about who was at fault – but one etiquette expert says there's a clear answer.

The video was posted to Twitter Feb. 8, but started attracting attention in recent days.

It shows a man sitting in a seat on an airplane and punching the back of the seat in front of him, which rocks forward with each blow – as does the woman sitting in the seat.

In the accompanying tweet, a user identified as Wendi says there were nine hard punches thrown before she started recording the 45-second video.

"Here's a great jackhole! He was angry that I reclined my seat," she wrote.

Replies to the tweet are divided, with some agreeing that the man was inconsiderate and many others saying the woman was actually at fault for reclining her seat – in part because the man was sitting in a back row, in a seat that could not recline.

"Why would you share this video when it puts you in such a bad light?" one Twitter user asked the woman whose seat was punched.

"If you can't sit in the seat normally for the duration of your flight don't go on the plane in the first place," added another.

Lisa Orr, a Toronto-based etiquette expert, says she was surprised both by the video itself and by the mixed reaction it received online.

"What I was really surprised at … was the Twitter reaction to the video. I could not believe the vitriol, how angry people were at the woman who put her seat back," she told Thursday via telephone.

As Orr sees it, the woman was well within her rights to recline the seat for the simple reason that she had been given a seat capable of reclining.

"In the end, the woman who put her seat back – she had a seat that reclined and she exercised that function. The man behind her assaulted her chair," she said.

"If someone butted in front of me at the grocery store … I can't get angry and then start whacking [that person] with my baguette. It's not an option."

The man is "the person who made the worst decision," Orr said, but the woman could also have handled the dilemma better by talking to the man before she put her seat back.

"A little bit of civility goes a long way. Recognizing that we're all human beings trying to get from point A to point B is really important," she said.

That's what Orr did when she recently found herself in a similar situation. Hoping to take a nap on a flight short enough that meals were not being served, she first struck up a conversation with the man behind her.

"I turned around and I said 'Sir, I was hoping to get some sleep on the flight, do you mind if I put my seat back a little bit?' He said 'Nope, no problem,'" she said.

"He might have also easily said 'Don't put your seat back; this is my space.' At least that way I would have known that if I chose to put my seat back … I was really taking something on."

Orr said airlines could also alleviate arguments about seat-reclining by removing the recline function, designing airplanes with more space between seats or suggesting during pre-flight passenger announcements that those looking to recline their seats first talk to the person sitting behind them.