Devils advocate: at least in the US they need to get rid of the thing that says sleeping in your car in the parking lot of the bar is a DUI.
That's literally a person doing the responsoble thing but the pigs can't help but salivate over the easy DUI they can add to their "not-a-quota".
It encourages people to drive drunk when they might have slept it off in the car because there's a chance you get away with it, whereas sleeping in the car at the bar is a guaranteed DUI.