Quote Originally Posted by NolLacnala View Post
1) Someone doesn't like someone and kicks them out, the kicked cannot rejoin for X amount of time. /no

2) Mentors can rejoin at any time, in the odd event that they've left NN. Moot point.

The solution already exists. Kick the gil seller.
It may not be the best solutoin but being in nn myself those gilsellers are awfully annoying. They leave themselves as soon as they are done sending their message so kicking them is not an option.
But I do think only letting mentors invite who are in the nn is not a good solution either. It would become much harder for new players to get an invite as they would no longer be able to just ask a mentor, but would have to find one in nn. And yes, mentors can rejoin, but the nn does get full at times so this is not always possible.