What are these "options" that you keep referring to, here and on other threads? The ref taking the option to ignore what he saw? I think that the consensus understanding amongst the majority of referees, here and elsewhere (I'm not claiming to speak for them here, only relaying my observation) is that the intent of the IRB directive is that the spear tackles and tip tackles without the tackler actively assisting the ball carrier back to ground safely are automatic red cards.
By the way, I don't buy into the legalistic approach set forth by Tonyowl (another newly-minted member of the site who's a Welsh supporter). I've been a lawyer for 15 years, I wrote an undergraduate jurisprudence paper on the interpretation of rugby laws 20 years ago, and have followed them closely ever since. The intent of the IRB statement is clear, and the legalistic interpretation of the word "should", which sometimes has been held by English courts in contractual interpretation to mean other than the imperative as distinct from "must", is putting to finer point on it. The plain English intent is that he should get a red card - it's only applying legalistic pedantry that one may argue that "should" creates discretion. If you followed the origin and circumstances of this memo from 2005 and the "big whinge" from the home unions about Brian O'Driscoll "incident" onwards, the clear intent of the IRB memo was to remove discretion, and have referees send off players for spear and tip tackles.
Now please, either give some substance as to your "options" argument, or stop clogging up the site with the gain-saying through your red-tinted lenses of every substantiated comment that is made trying explain something for your benefit.