I'm from a country where we don't have the Venturer step, upon their 18th birthday a Scout has the option of going up to the Rover Crew, or to do adult training and come back to the troop as a junior adult leader. Works like a charm, as there are never issues of dating, smoking, drinking, permits (needed to take children on events), etc. in the Crew. I imagine the well placed age separation has saved us a ton of legal nightmares. (FYI - 18 is the age of majority for most things in South Africa).