It’s tough to catch criminals when witnesses can’t identify them. To that end, a group of D.C. residents have proposed an idea that would make spotting robbers easier: ban the sale of ski masks.

The idea stemmed from a spate of robberies in Ward 4 where robbers that are thought to be part of a local crew hid their faces behind ski masks, making positive identification all but impossible, reports the Washington Times:

On a Metropolitan Police Department-run listserv, Ms. Wheeler was one of several people who broached the subject of trying to discourage the sale of ski masks in the neighborhood, or asked legislators whether there are other ways to ban their sale.

“I don’t know how you can get at it legislatively,” said Ms. Wheeler, acknowledging she meant to open the door to discussion rather than suggest her own cure-alls. “I don’t know that persuasion itself would work unless you have a personal relationship with a store owner.”

It’s already against the law to wear a mask if the person’s intent is to commit a crime, though the law is difficult to enforce because it relies on the ability to assess what a person is going to do before they have done it. Moreover, it doesn’t speak to the sale of ski masks, which are otherwise perfectly legal goods—and relatively commonplace in colder climes.