Bus riders, beware. Eating food, including pizza, can result in a costly citation in San Francisco.

A man experienced that reality the hard way back in March when he was handed a ticket, which can yield a $250 fine, for chowing down on a pizza at a Muni bus stop, according to the San Francisco Chronicle.

The citation was delivered on March 5 to a homeless man who purchased a pie for his friend's birthday before enjoying some slices at a bus stop located at Market and 7th Streets, the newspaper reported. The exact wording on the ticket referenced "eating or drinking in or on a system facility or vehicle in areas where those activities are prohibited by that system."

Consuming food while riding on most public transit vehicles is against the law, but those rules are seldom invoked, according to the newspaper.

A Muni spokesperson told the San Francisco Chronicle he was not sure if it's legal or illegal to eat while sitting at a bus stop. Eating on a Muni bus or inside a Muni station is an offense, but "food prohibition doesn’t necessarily extend to bus shelters," the spokesperson told the newspaper.

The man's ticket will likely be thrown out if the man can prove he is homeless and in search of services, the newspaper reported.