Recently a routine police patrol was parked outside a bar in Kilkenny. At closing time the Guarda noticed Tommy leaving the bar so apparently intoxicated that he could barely walk. Tommy stumbled around the parking lot for a few minutes, with the officer quietly observing. 

  
After what seemed an eternity, in which he tried his keys on five different vehicles, Tommy managed to find his car and fall into it. He sat there for a few minutes as a number of other patrons left the bar and drove off.   

 
Finally he started the car, switched the wipers on and off; it was a fine, dry summer night, flicked the flashers on and off a couple of times, honked the horn and then switched on the lights. He moved the vehicle forward a few inches, reversed a little, and then remained still for a few more minutes as some more of the other patrons' vehicles left. 

  
At last, when Tommy's was the only car left in the parking lot, he pulled out and drove slowly down the road. The Guarda, having waited patiently all this time, now started up his patrol car, put on the flashing lights, and promptly pulled Tomy over and administered a breathalyser test.  

To his amazement, the breathalyser indicated no evidence that Tommy had consumed any alcohol at all! Dumbfounded, the officer said, "I'll have to ask you to accompany me to the station. This breathalyser must be broken.'" 

  
"It ain't" said Tommy , truly proud of himself. "Tonight I'm the designated decoy!"