There was a particularly
volatile time during my LA County employment in the 60s when our work was
interrupted by a bomb threat about once a month. We'd abandon our desks in a flurry of paper and hike in an orderly fashion 4 flights down the back stairwell to the street below where we mingled with the protest of the day while the sheriffs department scoured the building for the bomb.
As time went on these phoned-in threats became more frequent. At least once a week we'd parade out and stand in the sun amid the picket placards and streams of people drinking Tokay and smoking joints.
Eventually the county higher-ups got tired of our loss of productivity. When the threats began arriving daily, they'd had it. A memo was issued. From now on we were to look for our own bombs. There in the heat of the day we were confined to our desks prodding through our drawers with pencils, lifting edges of paper, peering into trash cans. Soon after, the threats stopped completely.
Some theorized the threats might have been an "inside caper".