Among the very significant fraud and abuse changes in the health reform legislation, Congress made it clear that they expect the regulators to keep bad actors out of Medicare.  One of the techniques they will use to do this is the revamped and bolstered Medicare enrollment process.  In his new consideration of these issues, “‘Halt! Who Goes There?’: Coping with the Continuing Crackdown on Medicare Enrollment,” Daniel Shay elucidates the new rules, explains their practical implications, and then reviews 18 months worth of Administrative Law Judge opinions dealing with appeals of enrollment denials.  However, the challenge is not merely getting in the front door, but maintaining enrollment, and the administrative burdens have grown exponentially.  This is a burgeoning area that all providers need to pay attention to.