LOL! Actually, I'm pretty damn near certain rendering someone completely vulnerable to a death stroke using magic, even if it's not the magic that directly killed him, would get you a trip down Lawbreaker road.
Remember ... it's all about intent. Plus by knocking him unconscious, you've robbed him of free will and the ability to even remotely defend himself against that which will kill him.
That line of reasoning leads to Lawful Stupid behavior, where Wardens would be a joke since they can't kill anyone because of ridiculously restraining rules. Intent only matters in terms of the magic. If you think it is OK to knock someone out with magic, then that's different than thinking it is OK to KILL with magic. It's the same difference as a police officer thinking it is ok to detain someone he just saw kill someone else, and thinking it is ok to shoot that person when they aren't a threat. Let's assume it is 100% certain the criminal will get the death penalty, that doesn't make the two acts equivalent. In the same way, how you use magic follows very different rules than how you use physical or other capabilities. Killing with magic is different than disabling, even if you plan on killing the person anyway.
Otherwise you get very ridiculously things. A warden goes to stop a warlock, who has is protecting himself with magic. The warden knows he has to kill the guy (warlock!), so by your reasoning he can't disable the magic shield, as that's just one of the steps towards killing him. Similarly, the Warden couldn't use magic to ever help apprehend a warlock, since he's clearly intending to track the guy down (and later kill them). On the helpless thing, that reasoning leads to a Warden sneaking up on an unconscious warlock having to wake them and make sure they can defend themselves before attacking. That ends up neutering Wardens so much that they are worthless.
In any case, the Laws of Magic aren't about robbing people of free will in general. They aren't even necessarily about robbing people of free will (you can imprison someone with magic just fine). They are about a select set of uses of magic that twist the mind of the practitioner.
This is the same sort of flawed reasoning that can make Paladins very hard to play in D&D. The Laws aren't about people being nice, fair, generous, friendly, good, evil, or whatnot. They are about a particular set of behavior AND intent WITH MAGIC and nothing more. Lose the behavior, lose the intent, or lose the magic, and you don't have a violation.