Opting out means sending a form to the State, have it returned, and have it notarized, then giving it to the school.
They only 'allow' you to opt out for religious or moral reasons. A simple "No thanks" won't fly.
It's like you have to justify your kid not having something government has no right to force on you in the first place.
"Opting out" just sounds easy.
There shouldn't be a law requiring it at all. But there is. EO's suck. Of course, some people love 'em, depending on the topic at hand. If one truly believes the vaccine is dangerous, then the process shouldn't be much of a hindrance.