You may encounter a plot like this in a bad spy novel. It goes something like this:
A top ranking anti-terrorism official enters 10 Downing Street clutching a folder containing a “For your eyes only” document. He briefs the Prime Minister — about an ongoing stakeout involving potential terrorists — and walks out. The only problem is that the folder is a standard MI5 issue — transparent! Inside the folder is a printout of a Powerpoint presentation with large fonts and bright colors. The bad guy armed with a camera and telephoto lens takes pictures of the transparent folder and gets the same briefing the Prime Minister got. The terrorists are tipped off and they escape.
The scary part is yet to come. This is not a passage from a spy novel. It really happened a few days ago. In real life, "the bad guy" was a reporter with a telephoto lens. Fortunately, the screw-up was discovered in time. However, this forced the authorities to move in right away and make arrests — before their investigation was complete. After the arrests, the top ranking anti-terrorism official who posed outside 10 Downing street with the transparent folder, Quick[ly], resigned.
It seems that this is not the first time it has happened.