Badges in full view and police radios on the table weren't good enough for a Denny's manager in Belleville, Illinois, who ordered five on-duty detectives in plain clothes to stash their weapons in their cars or leave the establishment.
David Rice told the detectives that only uniformed police officers were allowed to bring weapons into the restaurant, and showed them a sign on the door indicating as such.
The detectives, who were in the middle of a meal, were told by the restaurant's general manager on their way out that they could stay but decided to leave anyway.
"It's absolutely a slap in the face I totally agree it's completely disrespectful," Belleville Police Captain Don Sax told Fox 2 Now. "How can anyone think to tell a police officer you can't be in here with your gun... it's absurd to me."
Sax says he's ordered his officers to boycott the local Denny's in response to the incident.
Denny's released a statement saying a "misunderstanding" arose after a customer noticed the officers' weapons and complained. While there is a Denny's policy not to allow firearms in the restaurant, law enforcement officials are not subject to that policy.