How to identify them?

Most likely they are:

A.  Hand-written  (Wal-mart does not handout hand-written W-2s)

B.  Wrong Social Security and Medicare withholding amount (The TPS will flag you regarding to this)

C.  Relatively high withholding (He/She makes $30,000 and withheld $10,000 for income tax.  This way they will get their refund)

D.  They "look" suspicious.  Usuaully they work as a team of two.  One will hand you the phony W-2 and the other will coach/be on the lookout.

If you prepare any of these during the tax season, please inform our District Manager and your office leader immediately.Do not act that you are excited!  Do file the tax return!  Do not give them the check! Have them call HSBC Bank!

http://www.irs.gov/compliance/enforcement/article/0,,id=163044,00.html