Guess they want to make sure its the same person coming in to file the return each year, not a roommate/family member or friend that stole the clients mail and has their W2 and showed up at your office trying to file a bogus return....wouldn't be an issue in a small office like mine, I recognize my clients by their voice on the phone I've been seeing them so long.  But a larger office with multiple preparers seeing thousands of clients each season, it can be an issue I'm sure.

I have to show ID at my doctors office (HMO) for a visit or lab work EVERYTIME, just so they make sure I'm me and not someone else trying to use my medical card.