Marc Grossman, the U.S. ambassador to Turkey in the mid-1990s, recalled telling his staff to take their own security precautions. After losing embassy employees to attacks, he advised staffers to keep a six-sided die in their glove compartments; to thwart ambushes, they should assign a different route to work to each number, he said, and toss the die as they left home each morning.
That's a good idea. I wonder if anybody just told their employees "take different routes to work" and found that their people decided which route to take based on, say, the day of the week -- having more than one route offers some protection from ambush, but there's still a pattern involved, and eventually the would-be ambusher would figure out that if they come by a certain spot on a Tuesday morning they'll succeed.
(Of course, there are still only six possible routes. If one wanted to go really crazy, one could toss a die at each juncture to decide where to go... but then who would ever get to work?)
This reminds me of airport security people who are randomizing where they are in the airport in order to thwart terrorists.
(from Marginal Revolution.)