No, that would be getting absurd. Most treasure hunts are just treasure hunts. I doubt you were being "comms trained". If you were then I doubt you'd be posting here about it and symbolism talk (even if you didn't succeed) would make a lot more sense. You'd be more advanced at it than any of us. Light bulbs would go off as you saw it.

We're talking about a different level. Were you asked to figure out complex ciphers, anagrams and complex codes? If not, then I doubt you were being trained in decoding. For you and most kids it was just easy scavenger hunts and word puzzles. What Dan Brown describes is on another level.

Remember 95% of the world population (probably higher) is not comms aware.

Most children are just having treasure hunts. Most people just go through the world without a clue. I doubt any treasure hunts you did were anything more than just innocent fun. You'd have to have at least one parent who was good at it enough to train you. Did you have a parent who was good at breaking code and interpreting symbolism? If not, then you were just playing a kid's game and nothing more.