I agree it is up to a buyer to maintain accurate records. I cringe when they ask me to ship to a different address; if it is worth more than a few bucks, I tell them that PayPal insists that we send to the address on file with PP, and would they please add that to their account.

As far as eBay's address records, if you click on "send invoice" or "print shipping label," either one will show their address on file. This helps when I have to do combined shipping and need a ZIP code or nation to do the final calculation.