I would also expect the internet (civilain access), GPS and a few other technical assisting devices to not be available for use in certain senarios...
So pick your “spots” wisely...And keep the info to yourself...
Deciding who you would tell in the event you are unable to retrieve said device, is kinda tricky...I’ll leave that to each individual how to protect that information and how to reveal that to someone else if that situation occurs...
Good point:
For those ultimate SHTF/TEOTWAWKI situations where one would most likely use a GPS to place find a cache, GPS may very well be shut off right when you need to find it.