I disagree with the opinions of others on this thread.
Just because someone buys an employee discount ticket, doesn't mean they should have known that it was suspect. Maybe to her, she might believe employees are allowed to buy discount tickets for others.
I agree that she should have done her due diligence but she probably doesn't know all the in and outs of air travel like most posters on this forum. To her, she saw tickets at a good price and purchased it. We know often in these cases, it is too good to be true but if everyone was so diligent we wouldn't have all these cases of people falling for fraud and scams all the time unfortunately.
Air Canada should beef up their anti-fraud techniques rather than going after her since it took them over a year to find out.