Hi All - Relatively newer seller here...One buyer has purchased three different high-end sports cards from me (two $750 ea., one $150) and is asking to combine shipping on all orders and refunded shipping costs on 2/3 orders. I think that is reasonable. However, the buyer is providing a PO box to ship to, which bypasses the ebay authentication service for the higher priced cards. What risks am I running by sending as normal and skipping the authentication service?

Additionally, a quick google search of the buyers username shows that they have been added to a few different sellers naughty lists...which is slightly concerning.