Just ask Tshwane metro police. They fined a Pretoria businessman R300 for doing just that, then slapped on another R100 for his failure to have "the required documents".
Disciplinary steps against the official are being considered after he failed to sign the bizarre fine.
Pretoria regional court senior prosecutor Marian van der Merwe quashed both fines on Wednesday. She said the businessman did not wish to supply his name for fear of victimisation.
"You can't fine someone because he or she is driving around in a Porsche. The second charge is just as vague. The fine does not specify which documents the official is referring to," said Van der Merwe.
Metro police spokesperson Mel Vosloo said the fine was a great embarrassment and would not be tolerated.
"Measures are in place to prevent mistakes like this from happening again. Officials are constantly being sent for training to be able to write fines," he added.
"The make of the vehicle should not have been referred to and the wording of the fine is vague," said Vosloo.
In February metro police came under fire for writing bizarre fines.
Take Willem Smit. He was fined R200 because his "tail lights burned when the car was in reverse".
Or Kobus Ludeke, fined R200 for having breaklights "in good working order".