The phone book lists the West Baltimore storefront with the green door as a social club, but some members admit it is really a front for organized crime.
The crime, mind you, is a non-violent misdemeanor carrying a maximum fine of $100. Club members are gray-haired guys who wear tweed caps and sport coats. And these grandfatherly desperadoes provide what some people, including elected officials, regard as a vital public service.
They use their late-model U.S. sedans as unlicensed, illegal taxicabs -- what in some cities are known as jitneys or "gypsies" but in Baltimore are called "hacks."
"It's making a living," said "Mr. D," a 10-year-veteran hacker and a senior member of the West Baltimore club, who spoke on condition he not be identified. "It's just a few extra bucks for people who didn't get a good pension."
Operating mostly in black neighborhoods, hackers generally work part time, driving families to and from the supermarket, taking elderly people to doctor's appointments and ferrying children to school. Regular taxi companies "don't want the people we drive," said Mr. D, who pilots a big, meticulously maintained Ford and wears an Army field jacket.
The West Baltimore club's hackers earn between $50 and $200 a week, depending on how often they drive, he said. Police familiar with the neighborhood are generally aware of their operation, Mr. D said, but leave them alone. "We give a lot to charity," he added.
Several officials of the Maryland Public Service Commission, which regulates the city taxi industry, said they were unfamiliar with hacking. But according to Z. Andrew Farkas, a Morgan State University professor, hackers have been an important link in the city's public transit network and underground economy for 75 years.
Cab company officials and regulators stress the perils of riding in illegal cab, which has no meter or set fare, has not been subject to annual inspection and whose driver may have a criminal record and may lack the required insurance.
But some politicians and others say it may be time to stop treating hackers as petty criminals: Maybe they should be hailed as transportation pioneers.
"I think hackers serve a very significant purpose, and I think we should perhaps look at legalizing it," said Delegate Elijah E. Cummings, D-Baltimore, the vice chairman of the House of Delegates committee that reviews legislation dealing with cab regulation.
"We should open our eyes and realize that there is a market out there, a market that is for the most part not being taxed, and it's not being regulated," he said.
Mr. Farkas, who teaches urban planning, sees hackers as a possible answer to one of the most perplexing transit problems facing the Baltimore region and other urban areas around the country: how to get poor city residents to the increasing number of jobs at factories, malls and office complexes scattered throughout the suburbs.
In Mr. Farkas' view, the state Public Service Commission's Depression-era taxi regulations could be rewritten to transform hacking into a legal jitney cab industry -- serving areas, routes and customers that the taxi industry and Mass Transit Administration can't afford to reach.
The city's legitimate taxi industry has been shrinking for two decades. Cab owners say they are plagued by a shortage of drivers, the city's declining population and higher costs, and they are asking the Public Service Commission for an increase in fares of about 74 percent -- on top of a 12 percent raise granted in November.
Some riders complain that there is a shortage of cabs and a lack of service. And the PSC is being pushed to consider sweeping changes to taxicab regulation in the city -- including a suggestion that it launch a study of partial deregulation.
If the commission wants a glimpse of an unregulated taxi industry, it need look no farther than Baltimore's hackers.
According to Mr. D, about 25 hacking clubs operate in neighborhoods in East and West Baltimore and Cherry Hill. Most of the clubs, he said, have 10 to 15 members, who are often retired or unemployed men.
Mr. Farkas said Baltimore's hacking clubs could trace their roots back to the jitney cabs that appeared in February 1915, charging a nickel to compete with the 10-cent fare of the trolleys owned by the United Railways and Electric Co. The PSC quickly adopted regulations outlawing jitneys.
Mr. D said some active hacking clubs had been operating since before World War II. "They have had the same telephone numbers for 50 years, and their customers know them by heart," he said.
His club, which is listed in the phone book, is about 20 years old.
Other hackers, operating as individuals, work out of supermarket and shopping center parking lots around the city. At least one market, several hackers said, helps organize hacking services by giving drivers badge numbers -- although none would name the establishment.