Restricts the WooCommerce checkout form for allowing PO Boxes for shipping addresses. If same billing/shipping address the customer cannot complete checkout with a PO Box as a billing/shipping address. If the customer is shipping to a different physical address they cannot use a PO Box as a shipping address, but can use it as a billing address. Does not restrict the use of PO Boxes on Digital/Virtual only carts. Requires that WooCommerce shipping is enabled. Requires that WooCommerce has a shipping method setup (can be free shipping only) Usage and extending examples can be found here: https://majemedia.com/plugins/no-po-boxes Github project: https://github.com/majemedia/MajeMedia-WC-No-PO-Boxes