I don't know. I don't know the whole story. You're right - maybe nothing at all. Entirely possible the family did nothing wrong and Westjet completely overreacted as is alleged.
I'm just saying that as a potential paying customer, I care more about how an airline treats paying customers and less about how they treat non-paying customers. For example some airlines cancel employee tickets last minute to avoid "bumping" paying passengers. I don't consider that bumping a passenger.