Hello ^^ i get few mounth ago these same asked and III too but the answer from Lilpro was post in one topic Teleport Restriction and he doesnt give the answer than one player can use this issue to use as a hack portal like for 20/30 zone or 1/15 for high level...
The instance as propose John is interesting but doesnt restricted the teleport and as suggerated lilpro was to write our Code to block it... i was testing many possibilities to block it and all time same Oi Caelum etc alll these are programmed in the game client too
for the moment i suggerated to use one query one script who can like exemple : item who give point game (itemmall) when selling... this kind of script to block the use but there are no warranty but get the merit to tested at default that someone understand the princip

willl post it link to the post of lilpro and III ...
In same way someone get One script of Automatic orange stat like on site Shaiya Freedom or Genesis directly per game... thx much
edit : just put the link of post

continious this thread it is interesting... But for all the instance doesnt block anything... so its more deep the modification ^^ Good Luck here the link