If it's all about safety, why not use fake cameras?

I have heard various estimates of the cost to install red light cameras at intersections ranging from $100K to $500K per intersection. While those costs are likely set artifically high by the camera companies who want to install them "for free" in return for a revenue share, there is no doubt that there is some significant expense involved. Business owners have known for years that a cheap and effective way to deter shoplifters is to install fake cameras. These are simply pieces of plastic that appear to be cameras but are really there to deter shoplifting.

If red light cameras were really about safety and not revenue as the politicos claim, why isn't there a proliferation of fake cameras? Wouldn't this discourage the so-called bad behavior? If a town wanted to install red light cameras, why not install fakes at all of the non-monitored intersections? You know why. It's not about safety. It's about revenue. Fake cameras do not bring in any revenue but they would likely engender just as much compliance as the real cameras.