Soreneck is absolutely correct. Although it's a novel concept, that would have no bearing whatsoever as a defense.
The contracted firms who carry-out photo radar in the province of Alberta are Sworn Peace Officers, under the Peace Officer Act. It's this legal status that allows them to issue tickets under the Traffic Safety Act.
http://www.solgps.alberta.ca/program...s/default.aspx
Peace Officers and Police Officers often have the ability to do things in the course of their duties that normal civilians cannot. Be it, carrying certain weapons, speeding to get to the scene of an incident, , having emergency lights on their vehicles, shooting suspects or even parking on the wrong side of the roadway - they are afforded many special privileges, exemptions and permissions as part of their appointments.