I don't think that those will be practical for the situation. Its an awesome thought but it would never get implemented. While the school is fairly decent sized for a private school in this area its not quite that big. And doing a quick scan of what pops up on google the cost is more than the benefit. There are only 3 outside doors. And once I get done there is only going to be one that the is accessible from the outside.

But that brings up another thought. What about a thumb print box on the visitors log?