I think you've missed the point of my commentary, if you think that's key here. Neither you nor I have access to that information; the school board, teachers, government workers, and parent representatives do, and they made a combined choice to implement this.

They could be wrong (and they have been before, of course) - but this family isn't arguing that. They are arguing on religious and privacy grounds.

Reductio in absurdum: take the "I won't do it because it's the mark of the beast" to it's next level (hacker news comments, library membership, news articles, theaters), and you have a dysfunctional society.