All for security but it can be funny sometimes.
Did a trip down to the Malvinas after the war on a MOD Charter.
On departure from the secret shared USAF base in mid Atlantic had to sign for the secret comms folder. On arrival in the Malvinas first bod on board was a RAF plod who took said file back and signed for it.
All good stuff except all the frequencies in the "secret" folder were in the Aerad supplement which was a standard part of the a/c library.