ALL US scheduled GPS outages (IE: scheduled jamming trials, specifically geographically denoted) are broadly publicised well in advance, via NOTAMS to pilots and notice to mariners.
Normally, these exercises take place well after 11pm, local time, to cause the least disruption to airbourne/marine GPS navigation users.
It goes further than just those two groups. There are other enterprises which have come to rely on the GPS system in recent times. A very high percentage of agricultural enternprises (ground as well as air) use GPS guidance systems for tractors and other farm machinery, and most broadacre agricultural operations are done on "autopilot" with the driver/operator there just to do turns when required and monitor the operation at other times.
Off thread I know, but GPS has become just as essential to these operations as it can be for mariners and airmen.