The technical English term for that technique is called “knife hand” and it’s one that has a home in many different martial styles. There is a difference: a knife hand to the back of the neck can sever the spinal column which will lead to death (this is why it’s barred from being used in MMA), a knife hand to the throat will kill the subject through asphyxiation. So, pick your poison.
Whether they are expecting it or not won’t change anything, it’s a straight up kill strike and it’s one that can be done very effectively from multiple angles.
I know this can be confusing, but there’s a much greater chance of murdering someone with an open hand strike than there is with a closed hand. Yeah, I know it makes Jade Empire seem rather ironic, doesn’t it? For example: a palm strike to the nose will drive the cartilage up into the brain and kill. A punch to the nose will…break the nose. It’s the method of application and the fact that the force is spread over a much smaller area than it is with a fist.
Movies avoid open hand strikes in general because they are more difficult for the actors and stunt men to whiff. Movies fake the hits with all sorts of tricks to make them look convincing but keep them safe for the individuals doing the act. Sports avoid them because, again, kill strikes and they don’t want the combatants dying. Sports are in the business of making money, unless they have a constant supply of fresh bodies whose training can be produced cheaply (like in Muay Thai boxing in Thailand where thousands of impoverished boys train for a chance at the arena) you don’t want to include attacks to vulnerable regions of the body that may cripple or kill your fighters (by pissing blood for three days because of a ruptured kidney).
The great irony is that an elbow to the back of the neck has a better chance of just injuring an opponent than a knife hand.
And let’s not talk about the fighting in Taken, unless we want Starke to go on at length about how wrong it is when paired with the main character’s background and profession.
…actually, don’t ask about it at all unless you want to see Starke foaming at the mouth. *flees*