There should be no problem if using ISM band of
(6MHz to 244GHz), but some military com. equipment use some specific frequencies, so we need to be careful, may be use a SDR to inspect the area and use anything that is free…
Most of our device are usually in the 2.4GHz so we are quite safe…
Oh yea, I used to wonder about that as a young graduate.
I believe now it is because the military spectrum has priority - so your device must not cause interference, and if important transmissions interfere with your device, its not their problem.