In my line of work, we convert words to numbers, and we have a codex that defines meanings for the numbers; that way, we can write publicly but (in making sure we choose words that, when converted to numbers, convert to numbers that have the second meaning we want) our public writing will only be understood on this second level with this second meaning only by those who use this system and codex. It's something like a form of real/human language cryptography: write for the world to see but only those who know the key will see what we're also saying to them. This was traditionally very hard to do for anyone who didn't grow up in a family that did this naturally from when they were kids. And I vibe-coded tools to make it easy. It's been amazingly helpful and worth its weight in gold :)
“Line of work”? I’m fascinated by this. Diner waitress? Cop? Carnie? Cockney bingo caller?
Hahaha! I love the list! Lots of professions have methods to send messages that simultaneously speak to various different audiences (while the bigger audiences don't know there are also other audiences as well, who will derive other meanings from the same message). The world is an interesting place full of surprises - and even to smart people, the text or image you are seeing might have meanings invisible to you, since you're not the intended audience for the secondary meaning.
What?