Good topic.  I'm the Pres of a video microstock company and every now and again we get hit with a spate of chargebacks - seem to often occur in Italy, strangely.  We have gone to lengths to fight our gateway (fraud protection) and merchant services provider for their lack of culpability in the matter.  We will have paid out commissions in excess of $20K that some months later is declared "chargeback," and have no recourse.  I cannot see fit to recoup that money from the contributing artists, because they, like us, had no culpability in matter, so it doesn't seem fair that they suffer the burden.  We have launched independent investigations to find that many times the chargebacks occur when agencies buy the footage on behalf of a client who in turn either changes course or fails to pay the agency, leaving the agency to call the credit card and declare the charge a fraud.  Thus we (and sometimes you) apparently are left without a chair.  Obviously to me, the onus falls squarely on the credit companies and the gateways, as neither we, the merchants, nor you, the artists, have any role in preventing the fraud in the first place.