Pearson Airport security snafu that caused Brazil-bound flight to redirect is Canada’s latest baffling border breach

When someone manages to stroll through security at Canada's largest airport without being checked, apparently board a flight bound for Brazil and force a full-on terminal shutdown, you expect there to be one heck of a story.

You can also expect that, whatever that story is, airport officials and security agents won't be quick to share it.

That seems to be the case in Toronto on Thursday, one day after a man reportedly walked through a security checkpoint shortly before 11 p.m. without being checked.

The breach led to a police investigation, the temporary grounding of all flights out of Terminal 1, and a Brazil-bound Air Canada flight being forced to return to Pearson Airport.

Passengers on the rerouted flight told CBC News that, once the flight returned to Toronto, armed officers boarded the plane and arrested a passenger.

Peel Regional Police confirmed via Twitter that they assisted with a security breach at the airport but, not surprisingly, officials with Toronto Pearson International Airport weren't quick to provide details.

"The (Greater Toronto Airport Authority) takes all issues related to airport security very seriously, and as is routine, will complete an internal assessment," reads a brief statement released by the airport's media office. "In the interim, enhanced security measures have been put in place. Given the incident involves airport security, we cannot share specific details."

For now, little is known about how the suspect made his way unimpeded from the unsecured area of the airport and onto a flight bound for the World Cup. Did it involve a disguise? A daring display of acrobatics? A door accidentally left ajar by a negligent employee?

Considering some of the notable security breaches in Canadian history, nothing is off the table.

Perhaps the most notable Canadian airport security breach occurred at the Edmonton airport earlier this year, when 18-year-old Skylar Murphy was found to have black powder and a pipe bomb in his carry-on bag.

The object was seized, though the security agent reportedly first tried to give it back, and the teen was allowed to board his international flight. It wasn't until airport security alerted RCMP four days later that Murphy was tracked and arrested upon returning from his trip. Murphy pleaded guilty to possessing an explosive device, but RCMP said he had no intention of using it on the airplane.

Canadian border security was also found lacking along a New York to Ontario train line in 2012, when an empty train car rolled undetected from a New York rail yard, across the Whirlpool Rapids Bridge near Niagara Falls, and came to rest at an Ontario Via Rail station. At the time, the bridge commission's security manager said no train had ever before crossed undetected during his 16 years of service. Considering the train car was empty, the breach could have been much worse.

But the innocuous rail line security breach holds nothing to an incident last summer in which a Windsor, Ont., resident was arrested after swimming across the Detroit River and entering Michigan.

John Morillo admitted that he had been drinking when he decided to cross the busy shipping route, and the international border, and that he had been telling his friends he could make the trek for 20 years. A friend who watched Morillo begin his swim across the border called police when he became concerned for his safety, which was perhaps the only reason he was noticed at all.

Another notable airport security breach happened in 2010, when a man travelling from England to Vancouver, via Calgary, fell asleep during the last leg of his flight and woke up more than an hour after the plane had been emptied and stowed in a Vancouver service hangar.

Though the passenger didn't breach border security, he definitely fell through some cracks. The Daily Mail reported he was woken up by an aircraft mechanic about 90 minutes after staff on board the plane should have ushered him off. "Somebody's neck's going to be on the line for this," the mechanic reportedly said.

It is possible that the Wednesday night security breach at Pearson airport was an honest error or simple mistake. But considering it caused an hours-long delay for several outbound flights, and forced one flight to turn around mid-air, the full story is worth hearing.

Too bad we probably never will.