Awesome idea, thanks for sharing! I think it's indeed a great way to spread adoption to those you know, love and care about. However, nothing stops one from doing both that and what I proposed. I haven't done anything yet except writing the post, that didn't require much energy! For now it's at the discussion stage, I might try to do it after all and report back how it went. After all, the cost is a piece of paper, some toner and two 1 sat/vB fees if it doesn't work out.
I was thinking about on-chain feedback as well in case the stranger decides to join the game. Like an OP_RETURN tx to their address that tells where to find the next sheet with a key.