Other mistake: Claire Keesey the bank manager has the birthday May 19, 1978, making her age 30. That doesn't align with the crime witness date for 9/2011 - she should be 33. (02:41:15)
Other mistake: When robbing the bank at the beginning of the movie, Claire is somehow about to see the tattoo on the back of Gem's neck while he is standing, and she's lying on the floor looking up.
Answer: The bag of hair from the barbershop was used to throw off the police when they search the getaway car later. In other words they will find all the scattered hair and have the wrong DNA. This is what they do after the second heist. They never used one at the end since the cops already knew who they were.
Gavin Jackson