There's nothing implied about tacit knowledge being knowledge that you don't know others don't have. For instance in chess mastery, one is fully aware that you simply see the board in a different way. It's not like you're aloof of your own 'advantage', but then in lessons you work to gradually, step by step, instill such in the student. Some of the most successful teachers are those who themselves learned the game a bit later than average, enabling them to draw more heavily on their own path. For instance Mark Dvoretsky only earned the IM title when he was 28!