Red light cameras have been known to tag cars as having run the light because their bumper was 6 inches over the stop line. They’re generally run by a private company that works a deal with the city - the city gets a cut of the take from the cameras, while the private company makes a lot of money. As such there’s little incentive toward fair application of justice, and a lot of incentive toward getting as many violators as you can, whether they’re violators or not.
I’m never a fan of private industry seeking to profit by taking over a role that should be the government’s. Especially when that role involves law enforcement (which is why I also don’t like private prisons). There should be absolutely no conflicting interests regarding profit vs justice in the justice system.