Back in time, Swissair issued its own manuals. In the "Route Manual" were exactly the kind of items relating to terrorism mentioned above. In those pre-sept 11 days crews were advised to cooperate with hijackers etc. Very useful stuff for a future hijacker to know.
The manuals were kept by the pilots and were revised regularly - a job often done "down the route" where there was time to kill. Result - the old pages landed in the bin.
When I made representations about this, the result was a red stripe made on the sensitive pages - no reason was given to the crews. That made it easier to find the pages in the bin...