The Department of Defense says its next generation of GPS satellites wont come with an on/off switch for civilian users. Because the system was originally deployed as a military system, the military wanted the ability to degrade the accuracy of the signal or eliminate it entirely to prevent it from being used against them. But with GPS in everything from cellphones to tracking chips in store merchandise, the DoD long ago gave up any hope of keeping it a discretionary asset and effectively turned off the "selective ability" function in 2000.
This is a companion discussion topic for the original entry at https://www.avweb.com/news/no-more-dumbing-down-gps