http://us.battle.net/wow/en/forum/topic/3341758633

This is from a Blue

Correct. Having your character do something on a key press and another action on the release would exceed that one action per key press guideline.
And this is obviously from a Tim alt

Pwnboxer does not perform this automation and was written specifically to abide by the rules. It is also likely the most used software to multibox in WoW, possibly more than all combined. To give you some perspective, the author of Pwnboxer was also the CEO of Wowhead.

IS Boxer appears to perform this automation (it allows 2 actions per 1 keystroke) so it would appear to violate the rules as the Blizzard rep above has just explained it, and such violation could probably get you banned (according to the EULA/TOS, violating the rules can result in account termination). To give you some perspective, the author of IS Boxer is tied to botting software and gold farming.