This is just corporate politics, why would they let you make phone calls for free, when you could be using your minutes. This is a business trying to protect its revenue. There really nothing they can do to stop you from using it, except on there network, if your connecting to a wi-fi access point there's nothing in your way accept the protocols of the access point. Once wi-max is in full swing things will get a lot trickier...
What a waste of the court's time.