The man was nabbed by police driving his Porsche Boxter in the district of Pfäffikon early in the morning of July 28th 2012, according to the court evidence.
Officers stopped the motorist but when he got out of the car he forgot to engage the parking brake and the sports car started rolling away, 20 Minuten reported online.
He was ordered to submit to a blood test and was subsequently charged with drunken driving, the newspaper said.
The man argued that he was re-parking his car in a parking lot because he feared vandalism after seeing youths loitering around his vehicle.
He testiified that he wanted to move the vehicle into an area where the lighting was better, 20 Minuten reported.
His explanation cut no ice with the Pfäffikon district court, which found him guilty in May and fined him more than 10,000 francs.
However, the higher court overturned the decision, ruling that the police were “careless” in stopping the motorist while he was still in the parking lot, 20 Minuten reported.
The motorist maintained that he was fully convinced that the lot was a private area.
The cantonal court determined that while the parking lot was freely accessible to the public the driver had made an “error of fact”, 20 Minuten said.
And the court noted that the prosecution had not provided any evidence to show that the motorist was in the process of driving home, or out of the lot.