Usually, your only chance at "revenge" against a shady cab driver is just denying him a tip—or, perhaps less satisfying, yelling a few choice words over your shoulder as the cab peels away.
Government officials say that despite past efforts to rein them in, corrupt cabs are "still rampant" in the city; the most common offenses by drivers include tacking on extra charges, or getting creative with the cab fare calculator.
To report a bad apple, just call the city's English-speaking tourism hotline (02-1330), and they'll investigate. To avoid the worst situations, however, you can look for the city-run cabs marked as International Taxis, and whose drivers speak both English and Japanese. Meanwhile, in a contentious situation, we imagine that cheerfully asking the cabbie for his ID number might not butter him up—but it could pay off.