This is not even the tip of the iceberg – just a light mist over the summit.
During the game, you sometimes come across leaflets not with such messages and reminders, but with full rules of complete games. Like “Marble Nest”.
There is no screenshot at hand, but the rules are not especially secret...
"You must play this game in silence. Two hours before dawn gather the guests. Everyone picks a person for themselves. After that the guests must move silently around the house. Each intensely thinks about their own. Sooner or later you will hear a voice: “Birds, birds, gather around the marble nest!” Everyone must freeze. If the rustling continues, it means the game is over and you must stop immediately. Among you is an invisible one."
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And the legend of how all these notes got to the developers is quite unusual for a “purely PR stunt”.
Perhaps it will help you add some color to the project or choose a more elegant solution at the design fork.
Or at least amuse you.
The main thing is not to try to play by these rules in real life. They “resonate” with some strange psychological practices. They are not intended for live use.
However, this particular body at this point in space‑time is very close to being worth the risk...