Their opinion on banning for 3rd party software involves anything that is automated or does actions on its own. Broadcasting keystrokes is perfectly legal.
Although it is up to Blizzards discretion on what they run through their system. They have made it known that hardware devices that broadcast keystrokes are fine, and I've sent messages to GM's inquiring if using software to broadcast keystrokes was legal. It was sent to a supervisor who approved it and said as long as it does not automate or think on its own your fine.

So overall I think the risk chance is extremely low, but this is just my opinion.