WOW,how does the underbidder find the address?

That would be a trap for young players!

If you are bidding on an item you can pull their details and have them emailed to you.

I have in the past insisted on them having a paypal receipt when they pick up, either on a mobile device or printed if they absolutely HAVE to pay by paypal, I usually accept COD. 

Good policy stormness.

(I think you mean cash on pick up, not cash on delivery, unless you deliver. It is also an expensive AP service where they get the cash for you on delivery).

No, I meant pick-up, of course, trying to take shortcuts on my mobile, and saying silly things!

The only way I can accept credit cards is through Paypal so if I sell an expensive item then I feel I have to accept a Paypal payment in case the buyer can not afford the item so needs to use their credit card on a pick up only item.

Only you can decide if the risk of a credit card charge back is worth the money you will make by selling pick up only items and accepting the occasional Paypal payment.

Unfortunately all the receipts and checks you can do will not stop you losing a genuine bank chargeback if a stolen or cloned credit card has been used. if you had a receipt with a copy of the buyer's driving license with the address shown then you could go to the police as they would have committed a crime but you would have to go after them in the civil courts to get your money or the goods back.

Having said that the chances of it happening are extremely rare and only possible if the Paypal payment is funded with a card.

Many buyers, especially newbies, pay with Paypal for a pick up item not realising that they have no buyer protection and usually if you explain that to them and tell them you are happy to refund their payment so they can pay cash after inspecting the goods they will agree.

If you don't want to accept the very small risk of a bank chargeback then there s a way to list which does not discourage a safe payment method but preempts any attempt to use Paypal and pick up together.

You need to list with freight as the only delivery method and Paypal and cash on pick up as the only payment methods.

They then have to pay for freight, very expensive for most large items, or they have to pay with cash.