Not necessarily. Online payment is currently mediated by a few large companies, the largest of them having their headquarters in a single country. There have been cases where these companies made things difficult for certain classes of sellers (for instance, erotica/pornography), or where pressure from that country's government made these companies block all payments to a specific recipient. In these cases I have read about, the person making the payment (and the person receiving the payment) would be breaking no laws.