So when I set up my eBay profile I chose "do not ship to PO boxes" yet someone bid and won who only had a post office box.
As it ends up I do not care. The reason I found out I had chosen this was eBay was unable to invoice him and sent me a message saying so.
I sent the item to his PO box.
Why is this an option (what is wrong with PO boxes) and why was it not followed (why was he able to bid and win) when I chose this anyway? Silly.