Mighty PO Box Blocker

Does not stop people from checking out with a PO box. I was able to checkout with a PO box while testing it live on our site. It did nothing to stop me from checking out except add a free shipping method to the order that gave me a warning to enter a PO box. My default shipping still remained as an available option and I was able to check out with that option. But it did not do what it says it will do which was to stop people from being able to enter a PO Box. Uninstalled this app right away.