Agreed. I should have said that my concern wasn't related to our hobby, but to global commerce/air transportation. I'm not sure it would take a WWIII scenario--"space law" isn't well established, and (regardless) there could be lots of reasons even "minor" belligerents might feel obligated and justified to degrade a system that is being used to put ordnance on their people/assets/soldiers, regardless of who "owns" that asset. It could get messy. EMP, directed energy, jamming of uplink synchronization/control signals, kinetic attacks, etc: some or all are within the capability of many countries/groups.And if WWIII does break out, well, I don't think the accuracy of light-plane navigation will be anywhere near a major concern for any of us.
It is good to see the growth of receiver chipsets that can work with GLONASS and Galileo.