Well, yeah, but here in B'more a "hack" was unlicensed. Kinda an informal taxi system in minority neighborhoods. See, Baltimore has a real history of serious racism and segregation for a "Northern" city (see: redlining, white-only deed covenants, etc.). Taxi companies, even up into the 70s wouldn't take call-outs to Black neighborhoods, and would frequently refuse to pick up Black fares when hailed. As a result, an informal network of unlicensed "hacks" serviced those communities, and both driving a hack and hailing a hack for a ride are both referred to as "hacking". The practice persists, primarily because hacks tend to charge a flat negotiated rate that's cheaper than a commercial taxi service.