A suitably sociopathic individual could probably have a beneficial effect on the bike theft rates in a city by just going around to the places where stolen bike

A suitably sociopathic individual could probably have a beneficial effect on the bike theft rates in a city by just going around to the places where stolen bikes are sold and beating the sellers mostly to death with a baseball bat. That'd be an intriguing experiment for an economist with the right sort of anti-social personality disorder (which is all of them, so I feel silly making the distinction).