The New York Police Department is cracking down on the subway showmen who use the tight quarters of the nation's busiest transit system as moving stages for impromptu -- and illegal -- pass-the-hat performances. More than 240 people have been arrested on misdemeanors related to acrobatics so far this year, compared with fewer than 40 at this time a year ago.

Police Commissioner William Bratton acknowledges he is targeting subway acrobats as part of his embrace of the "broken windows" theory of policing -- that low-grade lawlessness can cultivate a greater sense of disorder and embolden more dangerous offenders.

"Is it a significant crime? Certainly not," Bratton said recently. But the question is, he added, "Does it have the potential both for creating a level of fear as well as a level of risk that you want to deal with?"