There was this policeman who liked to stake out bars for an easy job by watching the drunks and then arresting them. After a while, a man came out and started walking to his car. The man could not keep his balance and fell down several times. He finally found his car after wandering the carpark for a few minutes.
The man tried to open his door but couldn't insert the key properly. The policeman was thinking to himself that this dude was clearly drunk and continued to keep a close eye on him. The man put the key in the ignition and sat there in his car. He blinked a few times and then did nothing. The policeman goes up to him and pulls him out of his car.
The policeman gives him an extensive sobriety test, just to take up some time and have some fun with the guy. After several minutes of this he orders the man to breathe into the breathaliser. It reads 0.0. The cop is puzzled and says:"I'm sorry, but I think that this thing must be broken."
The man replies in a surprisingly sobor voice, "I doubt it, I'm the designated decoy."