In some cities a lot of striders on the top list are Private. Maybe some Private striders are not even aware of the fact that they are Private? They see themselves in the list and some others (non-Private). Maybe some kind of notice text in an appropriate place when looking at a list of striders in a city. So only if you are a private strider, you see a little info “Note that you are private, so other striders won’t see your accomplishments”