There's a national foliage database that basically breaks up USA land mass into small lat/long chunks and assigns a foliage type (grassland, deciduous forest, etc.); Its possible they're leveraging that database for giving out the initial beta golden tickets. As time moves on and more sats are operational it makes it easier for the constellation to maintain user connections in partial coverage areas (since satellite density will be higher) so one might expect corollary expansion of the user base. Higher latitude users (up to mid-50's ish) will always be in better off as satellite density will always be the highest in that region, and those users (Northern USA and Southern Hat) will almost always connect to sats at higher look angles than someone in the southern USA. That means those folks can always have a more obstructed view than more southernly folks and still get service.
IMHO, the UT will constantly be mapping its field of view and feeding that back to The Machine so The Machine can most efficiently route traffic, plan coverage, etc.
