You obviously do not know what you are talking about.
Try to put your thumb on someone thrashing about on the ground who does not want to be touched or cooperate in any way. Try to do it safely so that you dont miss and hit an eye or gouge the throat and damage the larynx. Or miss by fractions of an inch and apply too much pressure to the corotid artery causing a rupture. See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1344809/ for more details.
The tactic you are proposing is far more dangerous than the use of a taser. Nothing more that arm chair quarter backing.
You couldn’t be more wrong. This is how I was trained and used the method first hand. It worked/works like a charm. Pain compliance moves are a legit, legal and effective part of the force continuum. The pressure point I described takes very little force to gain compliance. Can’t imagine severing an artery, that’s just idiotic.