Yoshi's post about client server and cheating

[Laraul]

In order to prevent cheating, we cannot use the client only

You do not quote something like that without providing a link to the SOURCE. I have no way of verify if that statement is valid. And you are making assumptions that aren't backed up by the game's behavior. Takes much less time to toggle active/passive mode then it does to transfer things to a retainer. More so, this would not prevent the existence of a mail system or limit trades to 4 items.