Then you have NO security in place!
Not for crazed and criminal thugs. You would have to design an actual prison type facility to gain that type of security. And the fact of the matter is that the vast majority of the public does not want to change their way of life “that” drastically - in all the various venues that we go into (besides schools) to protect against every conceivable and outrageous thing that can happen. So ... with the public in general ... you’re never going to have that level of protection.
What this does ... as it is now (and as I said up above) ... is insure that the paperwork that was signed at the beginning of the year for who is to have access to the child and who the school is supposed to “hand off the kid to” is followed - according to that signed paperwork.
THAT is mainly what it is for.