Game Theory

The presidential motorcade consists of three identical cars with blacked out windows. This way, any potential troublemakers will not know which car the president is riding in. In the long term, it makes sense for Secret Service to use a random number generator to decide which car to put the president in. This way, it will be impossible to predict his location. However, in the short term, it would be in the Secret Service’s best interest to put the president in the car at the back of the motorcade. This last car has the benefit of going through tested territory; the other two cars have cleared the way for the third and have helped to ensure that it is safe to drive through. 

So the dilemma: every time the motorcade is formed, the Secret Service should rationally put the president in the last car. But, if they do this every time, eventually people will catch wind and the whole motorcade system is for naught.