C
Cooking
Legend
Platinum Level
I don't know of any sites that offer this. As for P2P, this can only be done with someone you trust very much. Transfers can be reversed if disputed, and Paypal tends to side with those that initiate disputes. So you can be scammed easily.
PayPal doesn't allow any gambling-related transactions, and I'm pretty sure that's worldwide, not just US.
Otherwise, PayPal themselves are entirely trustworthy, and who they "side with" in a dispute depends largely on the parties involved among a ton of other factors.