Many years ago, I worked temporarily at a facility that had been converted from big-time classified government research to a benign peaceful purpose. Most of the former employees were able to transfer to the new projects. The facility was a complex of buildings surrounded by a fence, with a guarded gate.
Old timers told me that one of the biggest issues was unauthorized photography. If you were caught with a personal camera, it was confiscated and the film developed. If, as one guy told me about himself, you forgot to take your camera out of your car after attending a kiddy birthday party, you got the pictures back, as well as a royal chewing out. If you had actually photographed something, you didn't just have employment problems, you had legal problems.
They didn't routinely inspect every car leaving the site, but there were random days when they did an inspection blitz. You could tell because there was a long line waiting to leave. And because, scattered along the roadside were all sorts of things that had been jettisoned by waiting employees. Rarely cameras, but typewriters, boxes of office supplies, tools, and that sort of stuff.