here is another part of the story that isn't told on the link above:
https://www.fox4news.com/news/americ...ar-travel-hack
Parsons confirmed his son was skiplagging and said the family has used Skip Lagged, a website that specifically lists hidden-city ticketing trips, for at least five to eight years to save money.
I don't think AA acted out of the blue. If the family has been skiplagging for years (except the son), I guess that the whole family was flagged and that their suspicion about the son was correct.