There is a tide of creeping (if not leaping) 'big brotherism' in this country at the moment, with tens of thousands of surveillance cameras being put up on public streets; facial recognition software, monitoring of phone & e-mail communications; laws allowing searches without notification before, during or after... including library and purchase records.
I suspect there's a law enforcement motive in the notion of GPS tracking of private vehicles.
And if you think we're not all under satellite surveillance... well, just take a look at these startling photos:
http://www.museumofconceptualart.com/un_proof/index.html