In Rome the next day, we stopped at the Trevi Fountain, where tall Senegalese men were selling counterfeit Louis Vuitton bags and venders tended carts offering cheap magnets and paperweights.
Regardless of how effective the filters might be, the idea that the only thing standing between a functional GPS system and a constellation of space-borne paperweights is a private company's privately-developed, privately-operated filtering equipment... but then again, we love LTE.