The person that was initially the designated driver who acts drunk and leaves the bar so the local cop follows him and pulls him over while all the other drunks leave the bar while the cop is busy with the designated distraction.
Bob, the sober one, leaves the bar and pretends that he has a hard time putting the key in the lock...then sits there for a moment leaning over the steering wheel. He drives out of the parking lot of the bar and the cop follows him as he drives just a hair under the speed limit and sways a bit, but still maintains the lane. The cop can't stand it so he pulls Bob over and asks Bob if he has been drinking. Bob says "No officer...I have not." Of course...while cop is busy with Bob...all the other people leave the bar. Then the cop gives Bob the sobriety test and finds out he really is OK and Bob says..."I told you that I had not been drinking...I am tonight's Designated Distraction.