According to other news sources, this woman is alleging that she showed up at the airport 90 minutes before her flight and there were no agents available to help her on time to allow her to make her flight. 

As a result she missed the flight and had to be rescheduled, with the attendant seating problems.

The crux of the matter is the question about whether she truly showed up 90 minutes early and whether her allegations of agents not being available are true.  If the allegations are true, Air Canada would likely be at fault for not properly accommodating her family on the next flight, because it was their fault that she had to be on that flight.

I suspect that something isn't true about her allegations.

Personally, I find it hard to believe that there were no agents available.  I've traveled a lot around this country on Air Canada over the last 10 years and I've never had a problem findings available agents in the two hours before a flight.