GPS is going to get better, and GPS tracking is going to get cheaper. GPS blocking or spoofing is also going to get cheaper, easier and more tempting for people who want to avoid surveillance and tracking. How long can this go on? Can you reliably encrypt a signal like GPS for everyone to use (receive) but nobody to spoof (broadcast)? Can you prevent jamming? Could this arms race lead to a general distrust in GPS technology and, therefore, a total abandonment of the idea?
Mokalus of Borg
PS - Probably not a total abandonment.
PPS - But how can you trust it if people can mess with the signal?