What's wrong is that reporting the income in those prior years is the incorrect treatment, and the OP knows that.
I agree with your general sentiment that we shouldn't audit or have to tie in every statement or tax form that a client receives, but in this case she and the client know that those W-2c are not proper, and I think that when we know that without a lot of extensive investigation but that it comes up in a discussion or that it's blatantly incorrect with a cursory look at those documents, then I think that not only do we have the professional obligation to prepare returns properly, we also have a responsibility to inform the client that those W-2c forms were issued in error. If we prepare returns with forms that we know are incorrect and we do not at least inform the client of that fact or suggest that they try to have them revised/corrected, then I think that might leave us open to penalty assessments and malpractice claims. These days, most accountant's malpractice insurance claims aren't from financial reporting, they are from tax-related suits.
Right, we aren't attorneys, but in the OP's client's case, the law that we are interpreting and discussing is tax law that dictates proper reporting on the W-2s of back pay to the SSA by the employer and to the IRS by the individual.