They use someone else’s credentials, reputation, and work history to get the job. They are fraudsters.
Think Stolen Valor on a civilian level.
Sure, I understand. It was just your characterization of them belonging to a "nationwide group" that puzzled me - as though they were members of a sworn conspiracy.
To my understanding, there have always been such scam artists and imposters. I should think that modern technology (the Internet, etc.) would have made it actually more difficult to pull that off!
Regards,