The Drunk Man

As related by New York Times writer Lawrence
Van Gelder in his "On the Job" column:

A police officer was assigned to stake out the parking lot of a
rowdy bar and watch for possible violations of drunk-driving laws.
Watching from his car, the cop saw a patron stumble out of the bar,
trip on the curb, then try to open the doors of a dozen cars before
finding his own car and collapsing in the front seat, where he
remained immobile. And where he continued to remain immobile as
the evening progressed and others left the bar, started up their
cars, and drove away.

Finally, with the parking lot all but empty, the patron pulled
himself to an upright position, started the car, and attempted
to pull out of the lot.

Immediately the cop pounced, pulled the motorist from the car,
and administered an on-the-spot Breathalyzer test. The result:
0.0% blood alcohol content. How could that be, the cop asked
asked the motorist.

"Simple," the driver said.

"Tonight I'm the designated decoy."