For a less dramatic example we’ve probably all encountered, consider traffic control before/after a crowded event or during an emergency road closure for an accident investigation or fire department response. Police routinely wave groups of traffic through red lights to keep things moving. Of course, receiving a ticket in the mail a week later for a traffic signal infraction would be …annoying… and wrong.
It would be more accurate to say that you can rely on statements from officials who are charged with interpreting the law.
Has this actually happened?
San Francisco has (in)famously done things like send a painting crew out to paint a curb red, even while there are cars parked all along the street there. Then, not only do they get red paint splashed on peoples’ cars, but then the meter maids come along and ticket all the cars parked there. Things like this made the news from time to time back when I was living in the area (early 1970’s).
Many states allow the cars in a funeral procession to proceed through a red light if the first car had a green light.
The red light cameras have become a thorn in the side for funeral processions. A quick google search has turned up numerous stories about mourners being ticketed. For example:
Yes, most municipalities say that a human is supposed to review the pictures for such cases, but apparently a lot of people fall into the cracks.