any delays are where the question gets raised.

the other would be the single keypress spawning multiple keys input to the client
ie:
F2 --> /say hey there bud wassup

in this case, 1 key press turned into 25 plus enter. definitely ban-able as per blizzards policy (1 key pressed == 1 key entered into the destination window)

and yes, AHK gets into these kind of grey areas.
the G15 keyboard is iffy.. and blizzard tolerates it due to logitech being the company they are.

if this weren't the case, keyclone would have had out-of-game macros a long time ago