As someone who received my first (and second - out of a running total of three I feel I should add) speeding ticket from a temporary camera, I have since tried to pay attention to camera placement. (Oh right, and to not speed, of course.) Intriguingly both DC and Montgomery County provide lists of such things, although not the temporary ones, since they roam. Red light cameras I worry less about, since I work hard not to run red lights, although certainly in stop and go traffic sometimes one ends up sort of trapped (which yes, you should also avoid, but sometimes the folks in front stop a little sooner than expected) in the box.
So, I was intrigued to learn in this breakdown of the results from one red light camera that you can both trigger the camera and receive a ticket simply by having part of one's car over the crosswalk line. And yes, I remember from driver's ed, and from being a pedestrian that one should not block the intersection or the crosswalk, but I wasn't aware that the cameras measured such things. I guess I assumed the sensors were placed farther into the intersection. So, just a heads up there.