couple years ago on the east coast of canada...
Guy was in the bar and had too much to drink. Did the right thing and called a cab.
Just then the bar kicked everyone out as they were closing. He waited outside but it was below freezing, so he got into his car to wait.
Cop saw him in his car...tested him and charged him with DUI because he was inside his car with the keys in the ignition (had his car on for the heater)
It went before a judge and finally some sense prevailed.
Driver brought out a rep from the cab company which had the time he called logged.
Brought weather statements showing it was fucking freezing out.
Had ticket showing what time he was charged
brought bar owners statement that he called cab from inside but was told to wait outside
Judge acknowledged that police were wrong to charge him as there were extenuating circumstances.
So there is the 1% time that the system worked sort of