I run a pretty foolproof system with paypal anyway. I link it to a debit card which is in turn linked to a second current account I have, which in turn has no money in it and no overdraft facility. When I wish to buy something using paypal I transfer money into the account and then pay for my items. Anyone hacking paypal will get coppers (if there are a few left in the account).
If I sell anything it gets removed from paypal asap.
Seems to work for me OK and makes me sleep easy.