distraction

There is a Police car parked outside of a local nite club, on a Friday night, at closing time.
The first patron out of the door staggers to a nearby car and tries to unlock the door with his keys.
Unable to open the door, he tries another car, again with no success.
He then staggers across the parking lot to his own car, and sits down inside.
Meanwhile, the other bar patrons file quietly to thier cars.
The first guy out starts waving and singing and saying goodnight to the other patrons.
Finally, after all of the other patrons had left, he gets in his car, starts it up.
Before he even gets the car in gear, the Policeman turns on his lights and pulls beside him.
The officer says, 'Get out of your car, I'm giving you a breathalyzer test.'
The patron agrees, and blows into the testing device.
The Officer checks the reading, and it is 0.0.
The patron then says that he had not been drinking that evening.
Confused, the officer asks him why he was staggering throught the parking lot, seemingly inebriated.
The patron explained simply, 'I'm the designated distraction.'