This topic never fails to cause problems and controversy every time there is a war in Medivia, religiously. The rules are too grey of an area to be read and properly interpreted. It has been said several times that the rules were to be re-written regarding what people can do and can not do with 2 characters online for years now.
The point of this feedback is for you to focus on figuring out the limitations within multi-clienting now, before characters begin getting banned for absurd reasons that you the developers or the players may find as a loophole for example.
It’s also been said several times over the years that you were considering removing the ability to multi-client on the same server altogether, personally I think this is the way to go. There is no reason people should be able to play 2 characters on the same world at once, it’s just going to continuously cause problems and in some cases (pvp), banned or deleted.