Decoding the Obvious: 35 Secrets Hiding in Plain Sight

Many taxi drivers use radio codes like, "There's an oil spill at ...", or "Cardboard boxes lying on the road ...", to warn other drivers of a police speed detection unit. There are other codes to tell other drivers that a popular taxi rank is empty (or full), or warn of drunk or obnoxious customers trying to hail a taxi. "There's a number eight at the railway station," might mean beware of a fare who looks likely to throw up in your taxi.

On a cruise ship if there is an announcement for the crew with the codeword "Niagara, Niagara, Niagara", followed by a location, it means there is a flooding situation on the ship.

A doctor may refer to a suspected case of tuberculosis as "Koch's disease" in order to avoid alarming patients.

On cruise ships a crew announcement calling for "Operation Bright Star" denotes a severe medical emergency requiring immediate attention, while "Operation Rising Star" means a passenger has passed away.

The color of twist tie on your bread bag indicates which day of the week that bread was made. This makes it easy for grocery stores to spot aging bread on the shelves. Monday – blue, Tuesday – green, Thursday – red, Friday – white, Saturday – yellow, Sunday and Wednesday are off.

Some hospitals, particularly in the US, use ‘Doctor Brown’ as a code to protect doctors and nurses, alerting them to the threat of violent patients in the vicinity. In some cases, paging ‘Doctor Brown’ will automatically send for security to come to their aid. Although the exact phrase used can vary, ‘Code Silver’ may indicate that the attacker is armed.

If you hear a time check announced over a loudspeaker in a store (it may sound like, “Time check, the time is 1:30″) it means there’s a bomb threat.

In hospitals and medical facilities, they have security investigate fire alarms before calling in the fire department unless the sprinkler system actually goes off. Since they cannot announce over the PA system that the fire alarm is going off, they "Page Mr. Gallagher" to a location. This is the code for security to investigate that location for a potential fire.

In online dating ads, if the girl mentions to bring roses, it is code for money and means she's a prostitute.

Any US aircraft using the code name "FLYNET" indicates that an aircraft is transporting a nuclear emergency team or a disaster control team to the location of a potential or actual nuclear accident or an accident involving chemical agents or hazardous materials.