One night, a police officer was stalking out a particularly
rowdy bar for possible violations of the driving-under-the-
influence laws. At closing time, he saw a fellow stumble out
of the bar, trip on the curb, and try his keys on five
different cars before he found his. Then, sat in the front
seat fumbling around with his keys for several minutes. Everyone
left the bar and drove off. Finally, he started his engine and
began to pull away.

The police officer was waiting for him. He stopped the driver,
read him his rights and administered the Breathalyzer test. The
results showed a reading of 0.0. The puzzled officer demanded
to know how that could be. The driver replied, "Tonight, I'm
the Designated Decoy."