Thanks for the heads up, officers
The police are allowed to lead sting operations to catch criminals in the act. However, what makes a sting operation a successful one is the fact that nobody except the authorities knows what’s going on. If you inform the public about what you’re doing, you’re not going to catch very many criminals. Well, not very many smart criminals.
Sadly, nobody told this police department not to announce their undercover surveillance to the entire world. They set up a sign and placed it on a lamppost, so passersby could understand they were being watched. They should have added text saying “Act normal.”