Code is used to address various situations.
Akin to Hospitals using code over intercom , still not scaring patients, and family.
i.e "Dr. Redstat please report to Ortho" - Red denotes fire, and in this example the fire doors and alarm have signaled in the Ortho unit.
I hate cats, so in various places "cat" was the signal a situation had come up.
Perhaps some folks entered, acting funny, casing the place...
"Oh phooey! Anyone tell Steve the Vet called and his "cat" is going to be okay?"
Practiced plans went into action, and fast!
To anyone else, this sounded innocent, whether in a business, or even seated in a diner and someone would say "how is the new cat?" - I knew they were concerned about someone coming in, or whatever.
Even as a kid, out with adults, code words.
Certain things meant certain concerns.
If I saw something and wanted to let others what direction, code was used, for where, I/we did not say left, right, behind, in front...
Say you and I are seated in the middle of a restaurant, facing each other to watch behind the other.
Someone comes in from behind me " how is the silly cat?" then the other person simply uses hands or moves salt shaker (whatever) to let me know, where behind me they are, which direction they are moving.
Instead of you looking up, making eye contact and therefore if the person is up to something, sees you watching them.
I do not have to turn around, instead I can scan behind you, and inform you of anything going on.
Make sense?
Just how I was raised.