As I said in the first thread dedicated to this topic, nothing about cleave requires using hide/invis. In fact, cleaving from hide/invis is effectively a violation of the hellion code, although people can and have tried to rationalize it away for a long time. And in that post I proposed a possible fix to that problem, although I'm undecided on implementing it.
Me wrote:
As for not being aberrant, these arguments that use hellions as an example are bunk. There's nothing innately dishonorable about using cleave. It doesn't require you to hit someone in the back, just that you attack first. Ideally, you have so intimidated your opponent that when you "magnanimously" give them the first shot, they use it to [REDACTED] their pants. Then you go ahead and take their head.
The hellion code forbids you to attack an opponent without first challenging them. It specifically states that a hellion finds it repulsive to behave like a rogue or assassin and that other hellions will not respect those that do. A hellion does not have stealth powers so that he can attack from the shadows. Stealth is used to increase his intimidation powers, because you don't dare to speak ill of them when they could suddenly tap you on the shoulder and demand your obeisance.
Granted people have been playing hellions (and paladins) badly since day one. I've had some thoughts about how to deal with this. One way would be that if you ever attacked when your opponent couldn't see you, it would automatically cause a blemishment that would have to be atoned. I could also see this in the case of paladins attacking other light auras.