Without any third-party* hardware or software may be more accurate, as what you describe is using hardware (your keyboard), and software (granted, it’s likely software that comes with your OS) to send keyboard commands to particular client instances.
Whether this may result in account actions or not is questionable at best, imo.
“We will now additionally prohibit the use of all software and hardware mechanisms to mirror commands to multiple World of Warcraft accounts at the same time, or to automate or streamline multi-boxing in any way.”