Thanks so much for your comments, giving some more background on this type of messaging.
You are correct about variations in the way the AT&T network is configured. It is the result of several corporate acquisitions, and, at least up to 2010, they had not made much effort to unify the different parts. If it ain’t broke don’t fix it, I suppose.
This kind of data collection has a legitimate purpose, but to get anyone at AT&T to actually talk about it was difficult, which was unfortunate, especially when someone is accused of texting while driving on the basis on one of these messages.