METRO'S TRANSIT police are a beleaguered lot -- 381 officers covering 1,500 square miles in two states and four counties, plus Alexandria and the District of Columbia. They perform an essential public service, for which we should all be grateful -- all, that is, except those among us who chew. As it turns out, the chewing public rides Metro at its own risk.

The facts are these: Stephanie Willett had devoured most of a PayDay candy bar when Officer Cherrail Curry-Hagler spotted her in flagrante delicto -- in the act of masticating -- as she entered Metro Center Station. The officer warned Ms. Willett that eating in the Metro system is forbidden, whereupon Ms. Millett nodded, kept chewing and popped the last morsel into her mouth.

There is every reason to believe that Ms. Curry-Hagler, an experienced transit officer, is a patient woman; she has four children under the age of 6, including toddler twins. But everyone has a breaking point, and apparently Ms. Willett pushed Officer Curry-Hagler to hers. Instead of heeding the officer's instructions, Ms. Willett advised her to tackle some "real crime." When the officer asked for identification, intending to issue a citation, Ms. Millett refused to stop, whereupon she was arrested, cuffed, frisked and locked up for three hours in a D.C. police station. She was released after paying a $10 fine.

To laymen, it may all seem draconian. But Metro's policy is zero tolerance, part of a broader approach of challenging minor violations in hopes of avoiding major ones. So far this year transit police have issued 308 warnings for eating and fined another 58 people. One may argue over the fine points; after all, why is gum-chewing okay but food-chewing banned? But Metro stands by its rule: If it's digestible, you are arrestable.