If paypal has rules forbidding currency trading how would the other user appeal to them to get a refund? What is he going to tell them? And how come they dont make any kind of investigation about it?
If a person does currency trading on paypal, then they usually don't ban the account right away but leave them with a warning aand point them towards the TOC. They don't however entertain requests for chargebacks by users involved in currency trading and they will usually just declare them to have lost the case since they were involved in it, and they do this without doing any investigation.
So basically its always the person who sends bitcoin for paypal, who will lose the case most of the times as the case will be won by the person who sent funds using paypal.