Hi David
If you see any listings in our Marketplace that request Friends and Family payment, please report them to the moderating team. That's expressly forbidden in our Marketplace rules, in the interests of the buyer's security:
"Asking Price: An asking price or price range must be posted (you may ask for a best offer in addition to your stated price) You may not solicit payment to be made via PayPal as a gift or friends and family payment."
As for sellers asking buyers to pay the PayPal fee, any breach of regulations is between PayPal and the account holder.
If @Adam has anything further to add, I trust he'll comment shortly...