The concern over jamming really doesn't apply to us airline guys. We've got plenty of backups. The concern is for the average GA dude. The FAA has been pushing next gen nav, decommissioning VOR's and NDB's and mandating ADS-B. This has pushed most (?) GA guys to use GPS as their primary, or in some cases only, nav. I've personally witnessed probable GPS jamming outside of NOTAMed air space. So if the military is playing nearby is all GA traffic grounded? If a pilot is near the NOTAMed airspace and is accidentally jammed. Is he a primary target only due to his jammed ADS-B transponder? We're going to a single source for nav options. Personally, I feel it's problematic. But who could have seen this coming......