They already do that. I got a red light ticket a few years back in Ottawa, it comes with a series of pictures showing me going through the red light. It was a -30 morning and cars exhaust was freezing at intersections, at least that's the excuse I gave at the hearing. I was presented with more pictures that also showed my speed at various points of the infraction. I STFU quickly and the nice lady reduced my fine by over half for showing up so we could review the pictures and determine I was an idiot for trying to make excuses.
Bad weather is a tricky excuse (I know I cite it). If it's raining, snowing, icy/slushy road conditions, you generally reduce your speed in order to adjust to the conditions. In my case, I'm usually doing the limit or thereabouts versus the 10+ over the limit I tend to drive on non-highways.
In non-icy conditions, you can generally slam on the brakes, you won't skid, and you should be able to stop in time if needed. So when they show you the ticket from the red light camera (shows 3 pics - license plate, you before the intersection with the light red, and you in the intersection), it's hard to argue. The funny thing I've seen is people who see the hand flashing, start slowing, and then when the light turns yellow, speed up trying to make it. I question the intelligence of that driver.
