You can deal with self buffing issue by suggesting no multi-client in pvp. Of course they can always be buffed by their friend or paying people, but that is my point, veteran player will try to befriend newbies to get their buff or there will be more zeny circulating through payed buff in pvp. Either way more benefit to server and to you for handling these self buffer.
edit: and to the newbies for having vet players for friend (to borrow stuff) or having new source of income.
