The FBI may turn to a new ploy to combat bank robberies: a dress code.

Special Agent Larry Carr plans to work with Washington state lawmakers on legislation that would forbid banks from doing business with customers who wear hats and sunglasses while inside the bank.

Carr, who heads the FBI's bank-robbery division in Seattle, said that most bank robbers cover their heads "with a hat, sunglasses or a hoodie [hooded sweat shirt]" to avoid being identified by surveillance photos. With most bank security cameras positioned in front of and above customers, the disguises are often successful because the cameras capture the bill of a cap or brim of a hat, he said.

"Even if you zoom in, all you're getting is the tighter picture of a baseball cap," Carr said. "Banks can spend billions of dollars on surveillance systems, and it's meaningless."

Carr said there have been 113 bank robberies in the state this year, including two in Seattle on Wednesday involving a man who wore a hard hat and safety goggles. Other recent robberies involved men -- and occasionally women -- wearing baseball caps, floppy hats and hooded sweat shirts.

Jeremy Stewart, 28 -- nicknamed the "Nomad Bandit" because he hit banks across the state -- told agents after his arrest last year that he knew the cameras would never be able to show his face when he wore a baseball hat, Carr said.

Many banks already ask customers to remove hats and sunglasses before approaching tellers, but customers often do not comply or bank employees do not enforce the policy, said Carr and officials at local banks. If it's a law, banks will have to enforce it, Carr said.

The Washington Bankers Association considered pushing for a similar law last year, but opted against it because members believed it was an issue individual banks should pursue, said association President Jim Pishue.

Carr's measure would not include bank customers who wear hats for religious or medical reasons.

Darcy Donahoe-Wilmot, a spokeswoman for Washington Mutual, said it has always been up to tellers to decide whether to ask customers to remove their hats and sunglasses. She said Washington Mutual recently started posting signs in its more than 2,200 branches across the country asking customers to remove all "hoodies, helmets and sunglasses."

"This is a brand-new initiative for us," Donahoe-Wilmot said. "Prior to this, we did not have a policy for removing sunglasses and hats."

Last year, All City Credit Union in Snohomish County posted a similar advisory in its branches. Bank Vice President Scott Prior said they also insisted that tellers at their four branches ask unrecognizable customers to remove hats and sunglasses.

Prior said that if one of their 5,000 regular customers is offended by the request, the teller is instructed to apologize for the inconvenience but still insist on removal of the items.

"If the robbers know they're being watched, and the tellers are observant, I think that helps your chances of not getting robbed," he said.

While Donahoe-Wilmot said Washington Mutual is looking into whether tellers should be ordered to ask customers to remove their hats and sunglasses, Shannon Ridout, vice president of security at Anchor Bank, said such a move is unlikely at her bank.

"It's going to be difficult to sell it to the banks because if you won't wait on them [customers], they'll go to a different bank," said Ridout, whose bank has 22 branches stretching from Covington south to Vancouver, Wash. "Banks are heavy into customer service, and they're all fighting for the same checking account."

Ridout said that instead of forcing banks to comply, lawmakers should outlaw the wearing of hats or sunglasses into banks.

"The banks have a right to install a policy to remove hats and sunglasses," said Jim Pishue, of the Washington Bankers Association, which represents more than 80 commercial banks across the state. "Banks don't have to do it, but it is encouraged because it does assist in the prevention of bank robberies."

Pishue said he would have to see what Carr is proposing before deciding whether to support legislation.

In the meantime, Ridout said, many banks have begun heeding Carr's advice that they lower their surveillance cameras to capture better images of robbers' faces instead of their headwear. Anchor Bank and All City Credit Union have lowered their cameras to 6 feet.

Ridout said the industry is slowly warming to the idea.

"I needed to get those cameras down so I could get decent shots," Ridout said. "I needed to get underneath those hats."

Jennifer Sullivan: 206-464-8294 or jensullivan@seattletimes.com