Are the lines not incase you are overtaking going in the right direction for the camera?

I know a guy that went through a regular Gatso the wrong way(with lines painted on both sides) at 100mph in a 30. He's done it a few times and it has always flashed, but he's never heard anything.

There are obviously the new smaller cameras which are built to get you going towards them though.

Don't take what I've said as fact, I'm just telling you what's happened with 1 camera. There might be updated Gatsos that get you both ways, I don't know.