Actually in most cases,the people running the photo radar units do not have signs preceding the photo radar unit as required by provincial law.They hope that most people do not actually know the law,and will not fight the ticket in court.If you get one of those 1kph or 2kph over the limit tickets,by the time you ask in court for calibration certificates and records,as well as the officers training records for the exact radar unit,the judge will usually dismiss the ticket.