Been away from the game for a bit, clarification if a TOS rule has changed

A buddy of mine is starting MB'ing soon and I was giving him advice. I was advising him on how to run the four shamans he plans to run and have it setup where pressing one button makes all four shamans cast lightning bolt or whatever at the same time.

He said he'd read that if one button press results in multiple toons casting a spell simultaneously it was a violation of blizzard's TOS...if so, this has changed since I MB'ed...

Is this so?

I thought it was perfectly OK to press one button, have keyboard broadcasting software send that key to all of your wow clients and then they all cast the same spell on the same target. That's kinda the core tenet of MB'ing...

You shouldn't listen to arm-chair lawyers.

1 button press = 1 action. even if its an action that takes place on 4 different wows. So your fine.

The software or hardware is sending the one press to each client.
So every client receives one press, and does one thing.