I hadn't heard that before Botach but having been in these situations so many times, myself and years of observing drivers doing these things, I have a theory..
I've often stopped where other drivers have zoomed past me and I think It's about going over the first set ON red. When they have gone over the first on amber but the second set on red it hasn't triggered.
I would hope that's how it works because that seems fair to me; but since when did fair come into road matters...
It's a good question Rob and one I've always wanted a definate answer to. I've been honked at from behind for stopping, when he expected me to go over on amber and follow me through. He hadn't a clue what I was trying to say as I pointed at the redspeed camera.