For someone who closely follows The Points Guy, I find this very interesting. Is there any precedent for a company restricting which 3rd parties I can share tracking information with? It's my information, my account. I wonder if American has a legal leg to stand on, or if they are just trying to bully people away from being able to use TPG's app instead of their own.
The closest thing I can think of is that I use the Shop app to track all of my deliveries. I give them access to my Amazon and other accounts, and when a shipment goes out, they automatically get it and put it in one place. This is basically the same thing.
The Choice to Maximize Your Travel