For my wife and I, our PayPal account is linked to our major credit card. Any purchase I make goes through PP, but gets paid with said card. That way we are double covered till the PP policy runs out anyway. I think that's why that one guy got his refund back.
I'll say this too, my wife set up our account. She put her name first on the account and then mine in our joint account. When I make a purchase, it always shows her as the buyer. Pinsiders I've bought stuff from can attest to that.
Anyway, Last time I had a problem (almost 2 years ago) they would NOT talk to me till they spoke with my wife first and got her info. I was pissed cause I'm jointly on the account. They didn't care and had to get her approval first. I only say this because I don't think PP would talk to anyone about anyone else's account for fraud purposes or not. If they did, it was either a major slip, a super sympathetic worker putting her job on the line or they have loosened that policy.
Main point, link your PP account with a major credit card for the extra protection.