We have had some instances where the shipping crew has shipped UPS Ground packages to PO Boxes. It's kind of an easy error to make since they aren't actually looking at the full addresses online, only name and town. But of course UPS ground does not delivery to PO Boxes. It would be great if you would build something into the system that would prevent this from happening. So basically if the customer address is a PO Box and the shipper chooses UPS ground, Shipping Easy would just say this is not allowed and would prevent that choice from allowing the shipment to be printed.