Hi there, I'd like to thank you for providing feedback on this subject, and the current Server & Forum Rules. I'm Lili, one of the ZetaRO admins and I'd like to address your concerns individually, if that's alright with you.
Firstly, the term AFK farming itself denotes that you are away from the keyboard and not actively playing. If you are using 4 clients and are watching all screens, then technically, yes, that would be legal as you are no longer AFK. However, please note that this will also carry the responsibility on your end to reply to a message from our GM team's manual