I think three very different things are being discussed re this 'point' on the occiput:
1. pressure on tendons and/or nerves which cause pain, useful only if uke can feel the pain and is willing to react to it...useless if uke's anatomy or drugs in system make him oblivious to pain, or he is willing to tolerate it.
2. blow to the back of the head, causing unconsciousness due to brain damage from the blow...as has been pointed out, and good sized hit will do in most any place.
3.knives can be used, as was pointed out, to 'pith' uke, as in either cut the spinal cord, or if pointing the knife in a cephalad direction, destroy the upper part of the cord and the lower part of the brain, that controls primative function such as respiration.
these three things are unrelated, the pressure on the point alone will not cause loss of consciousness unless uke 'passes out' due to a vasovagal reaction to the pain he feels, again very unreliable and very very uke dependant. This reaction is the same 'passing out' some folks have at the dentist, or if blood is drawn. I do find, however, it is usually the big guys that do this, so it may not be so useless...
but i sure wouldn't count on it