If you live in Jersey City, KNOW your fare. If you don't you'll pay something different every time and often be over charged. The good drivers will know when you're on par.
Hoboken ordinance only permits additional passengers in the taxi with permission of the 1st passenger. If you don't wish to let others in your taxi tell the driver. They "accidentally" forget.
To know Hoboken is to know that these cabs ain't like the ones across the river. They load 'em up full and charge per stop (don't let 'em charge you per person!).