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One night, a police officer was staking 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 the man sat in the
front seat fumbling around with his keys for several minutes.
By this time everyone had left the bar and drove off.
Finally, he started his engine and began to pull away. However, 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.
With a smile on his face, the driver replied, "Tonight, I'm the designated
decoy!"