Legal Liability for Emailing Credit Card Numbers

Certainly they both would be raked over the coals hard core. I wouldn't want to be either if the information gets out. I would instruct Company A to stop immediately as they are your client. Tell them the right way to handle this, if Company B isn't interested in playing along, ditch them and run away. Fast. Don't turn back. If they are willing to bend the rules here, where else are they doing it. Sounds like an invitation to trouble and pain.