Recently, I wrote a blog post about preventing PO box customer addresses being registered at checkout. Following on from that post, I was asked a rather sensible question: "is it possible to disallow PO boxes for shipping, but allow them for billing?" The answer is yes, but it does require a few more modifications to Magento.
Preventing PO box customer addresses
It's often undesirable to mail items to customers who provide post office boxes or locked bags for their delivery address when placing an order on a Magento site. Most commonly this is a requirement for fraud prevention or shipping reasons. Unfortunately, simply stating that PO boxes cannot be accepted somewhere on the site is often not enough to stop some customers from still placing an order with one. Rather then be left with orders that either require a followup or can't be fulfilled, an easy solution is to add validation code to prevent PO boxes and/or locked bags from being entered in the first place.
