I'm sure it varies by area.

Where I live they install speed cameras in residential areas, school zones, and bus routes. They also only trigger when you are going 12 or more over the limit, and the highest speed limit I've seen with one these was 45mph, 35mph during school times. They also have an officer review and sign the citation, it is a flat fee, and no points. If needed, the officer who reviews will testify in court.

If someone is going 12+ over on school zones, school bus routes, and residential neighborhoods, then they deserve their fine.