We offer shipping exclusively through UPS, but we have run into a problem several times where a customer enters a PO Box as the shipping address, we print the label and send off the product, and UPS doesn't make a fuss about anything until the package gets to its destination city. UPS doesn't deliver to PO Boxes, so they try their best to deliver it somewhere else, delaying delivery in the process. Please allow us to exclude PO Boxes from the shipping orders we receive. I would rather not ship at all than let a customer think everything's okay only to find out later that it's not.
Great suggestion @Floydman
I would also share this over to the Feature Request section as well, or see if a Mod can move it there.
Are you able to add a message during checkout for the time being or a banner of some sort stating you do not ship to PO boxes? May save a headache or two for the time being.
The simple answer is "Yes". However, we've learned from 5 years of online shopping that most people will not stop to read what they don't need to. The surest way to keep the customer happy and make sure we don't get PO Box orders is to make it impossible to place them.