The point made on third party audit is a valid one, some audit mechanisms will provide value to third parties and others won't. If you rely on a audit report or process which doesn't provide you (as the reliant party) any form of redress then it might give you a picture that doesn't give you any legal protection... The question you have to ask is what legal liability does the auditor have to you (on the basis you didn't commission the audit) if you rely on their findings