Not sure. I know the Paypal isn't supposed to dip into your checking account for money, but they've been known to do it. Usually, what they do for a chrageback is freeze your Paypal account while you try to dispute it. If they find in favor of the buyer, they'll add a negative balance to your account which, if not paid, will be sent to a collections agency. I withdrew mine to make sure that, if there is a chargeback, they wouldn't just steal it back since I did everything to Paypal's seller protection standard. I sent overnight with $2000 in insurance, sig confirmation, and return receipt, so his chargeback would HAVE to be fradulent in this case.
I'm sick of all these whiny buyers. It's their fault for not waiting. It's like buying a $50 game and then getting pissy because you missed the obvious price drop that was going to happen within a few days.