If attending school is associated with a high risk of terrorism, is that what the document asks you to sign? - you would theoretically not need to send your child to school. Strange thing. ...
When I first read it superficially, I just thought: So what? Nowhere is it guaranteed and safe. Do parents want cameras, automatically locking doors and security staff everywhere? Is this how children should go to school? If not - and the school, or whoever is the authority responsible for your district - thought that instead of cameras and security staff, they would simply leave the parents outside the school grounds, that might be the end of it, because no other adults pretending to be parents would be able to come in. But that's just a spontaneous thought. Who knows for sure. Have you checked with someone at the school who can provide information about what is actually meant?
In any case, we see this all over the world and everywhere: entrances are checked, bags are searched, at events, etc.