This was never really brought up in the patch notes for any updates with the mentor system, but if any new adventurers ask, it is nice to know for mentors.

New adventurers who do not want to be a part of the network can leave of their own accord with "/nastatus off" and they will be removed from the network and also lose their green leaf until they type "/nastatus" or "/nastatus on" to get their status back until they hit the final 2.55 quest or 168 hours played.

Hope this helps anyone who has had to answer the question "How do I leave?" from new adventurers!