RFID tags are not GPS devices. Most of them (passive RFID, i.e. the sort in your credit cards and pets) don’t “broadcast” per se and require a nearby reader to operate.
Powered RFIDs require a separate battery and antennae, generally have a fairly short range (few hundred meters, max), and are orders of magnitude larger than passive devices.
There’s no such thing as “military-grade encryption.” There are military standards for encryption (most notably FIPS 140), but they generally just specify algorithms and configurations. In this the Year Of Our Annuit Cœptis 2019, most modern consumer-grade technology comes with FIPS-compliant crypto configurations by default (e.g. Windows Bitlocker, macOS FileVault, iOS, etc.). It’s very difficult to “hack” but if you put a shit password in front of it, you’re still boned.
Incidentally, the “military-grade cryptography” thing is (asides from being a marketing buzzword) a hold-over from the pre-2000s era, when the US government did have export restrictions on certain cryptographic algorithms, effectively to deny anyone who wasn’t the US access to crypto the US could not hack.
These restrictions (mostly) ended when tech activists started getting tattoos depicting restricted crypto code, usually RSA implementations, effectively turning themselves into “restricted munitions” and tl;dr the laws got challenged and rendered unenforcable. Also, the internet happened.
Nowadays, some restrictions do still exist, but they’re fairly specific and almost never what anyone who uses terms like “military-grade encryption” is actually talking about.