Either did not mean either or in the sense you thought. Either meant the possibility of being sent a message on Character A or Character B. If I message you on MainChar to check for botting and you respond, great, no ban. If I message you on MuleChar to check for botting and you do not respond, MuleChar (and therefore all of your accounts) will be temporarily banned for botting. It's that simple.
Good lord when will the exceptions end? Just take the 5 extra seconds necessary to make sure your second client isn't mimicking the first. Anyways, a GM isn't likely to check if your botting if you're just walking around aimlessly. I do that even when I'm there. Seriously, what's the point in a bot that forces you to walk around and that's it? As you said, the mimick only affects the arrow keys, it's not like you're walking around killing things and affecting gameplay. You're way too worried about a nonissue.
So its fine if i play with window mode and see atleast chatbox of both or did i understand that wrong