While this information is true, there is no way for TiVo to know where you live in terms of locals provided by DirecTV without calling out. I know its not a forced mandate (in terms of land-line requirements and STB's) by DirecTV as my HD-STB has never been connected to a phone line.
If you have a neighbor with a traditional phone line that'll let you borrow it when you set things up for a few hours, forcing a couple daily calls on a new unit should suffice for the initial setup, then the phone line can be removed and you'd only need to worry about it again when you became aware there was a software update available, and you wanted the update.
With some brands of cell phone you can get an adapter to connect it to your house wiring and provide access to regular telephones. While generally this doesn't really support modem calls, I've seen people report having no troubles when forcing the calls to go at 9600 baud. It might be agonizingly slow to get a software update this way, but it seems that it functions OK. The DirecTV PPV accounting calls are already low speed so they work fine in this configuration.