When the foreighn telephone companies were allowed in México, Telmex had to compete with them for clients so they have changed a lot of the dumb rules that they had, when I lived in Cholula in the late 60's I could get a phone if I was willing to wait about 3 or more years and buy stock in Telefonos de México, persons having phones were called "abonados" because they had "bonos" and it was expensive.
I guess that they are using the RV parks phisical address for the installation, it is in their interest to have a client after all, we have had AT&T service since 1982 and had the special program for Mexico, the internet service has only been somewhat important for us in the last 10 years, with laptop's and phones that are more computer than phone we are covered since they have access to the cell towers, we have a USB internet stick a signal booster and a hot spot for travelling more so for Mexico than the USA.
Thanks for the information.
navegator