I only have one comment: if the person’s behaviour was so erratic prior to boarding, why wasn’t he intercepted and spoken to before? From the curb to the cabin, there are plenty of eyes and opportunities to confront erratic behaviours before they become unruly!
Excerpt from the article:
"He was buying a one-way ticket to Toronto but found out that it was quite expensive," said Taylor. The man then bought a ticket to Halifax instead but seemed unfamiliar with using a debit card and spoke in broken English. When the man boarded, he seemed confused and wasn't sure where to sit until a passenger helped him find the seat on his boarding pass.
"He seemed very anxious at the time," said Taylor. "He was looking around, he looked super, super-anxious."
He added that he overheard a flight attendant talking about the man making her nervous, which in turn worried Taylor. While the plane was taxiing down the runway, the man got up from his seat, prompting a flight attendant to take action. (...)
Read the entire article on CBC.ca: Unruly passenger prompts flight cancellation: 'I was extraordinarily scared. Like weak in the knees scared'