Here's an example of the greyness in this area, even from Bliz (emphasis mine):

On my G15 at home, I have plenty of the G keys macroed to /cast <stance> and a lot of other things. It's a keyboard string so you'll have to record it into the G keys as that. Usage such as those are fine. Doing multiple things on a single button such as ( walk forward, wait for so and so, tab key, /cast fireball(rank 5)) is the type of play that is prohibited.
...
Game and keyboard works fine. Just don't automate things too much and you will be ok. I haven't been banned yet for the G15. :P
http://forums.worldofwarcraft.com/th...321064&sid=1#2

It would be great to have an explicit definition of "too much". For now I'm taking it to mean 1) no delays, 2) no getting around game mechanics (multiple spells with 1 click), 3) no actions that are not easily achievable by a singleboxer by in-game means. Currently I only send multiple keypresses for my "spread out in a line" button (the extra keys are walk on/off to stagger the line). I think that's ok because the action is 100% controlled by me and the multiple keypresses only provide a limited version of something that singleboxers take for granted.