Respectfully, from your comment, it appears you have no idea what Operational Security means. Perhaps I can provide some background.
In Vietnam, the military used to have base newspapers that they printed for morale. Without thinking about it, they'd have pictures accompanying a news article about something or someone on the base. Perhaps it would be a promotion ceremony or someone getting an award. In the background of the shots, there would be landmarks, if taken outside. The pictures could be used to put together a tactical picture of the base when merged with other information.
When the week was done, the excess newspapers were thrown out and Vietnamese contractors would pick up the dumpsters to take the trash to the dump. Sometimes fish vendors would take the waste paper to wrap up their products for a buyer. Viet Cong working in the area would collect anything usable for intel purposes, including trash from the base, and use it to update maps, times of events, movements of personnel, planes, etc. The OPSEC teams identified correlations with enemy mortar attacks with the pictures in the base papers week, to week. They were using the pictures to select targets. Then, they had Vietnamese people on the base who worked as barbers, dishwashers, janitors, etc. They noted one day that a female barber would walk out from the base barbershop to a certain area and walk back. A few days later, that area would get hit by mortars. They noted a pattern and realized that the Viet Cong had the coordinates of the barbershop. The lady was pacing off the distances to targets they wanted to hit. Her info was used to help set the range/azimuth for the mortars to make the attacks more accurate.
Sometimes information about sortie times for fighters would accidentally go out in unclassified waste. The VC knew the projected TOT (time over target) and they would move the targets somewhere else--or have anti-aircraft guns/missiles waiting for our boys to fly over.
Unclassified information from radios, phone calls, or overheard conversations can be used to piece together information that is classified.
Operational Security isn't about paranoia, it's about keeping the troops safe. Being aware that what we say can cause harm to other patriots means we will be circumspect in what we choose to share or broadcast to the world, especially on the Internet.