GPS privacy/ECM

I have been following the recent discussion on Denning's GPS I.D. plan and had some thoughts: I wonder what the pro-govt anti-privacy types would do if some obnoxious group started publishing a list with the home/work GPS of say various congresspersons/senatepersons? Since cruise missile's already use GPS to find/destroy their target, how long do you figure before some terrorist group use's this ever cheaper tech to trigger one of it's devices? <car bombs, the poor man's air force> What defences are there? Just how small/inexpensive could a home GPS/ECM system be? Personnel dithering? Locally transmitting your own public key encrypted location. This is thoughtfood only. Brian