New York's nightlife has often been defined by its crazy edge. During prohibition, the city had its share of illegal drinking dens, or speakeasies. And the celebrated ones, such as the Cotton Club and Copacabana, had their share of controversy. In the 1970s, Studio 54 was known for its anything-goes hedonism involving celebrities, beautiful people, sex, drugs and disco. Meanwhile, the club CBGB in lower Manhattan was giving birth to punk music. As for the 1980s, the novel American Psycho captured the obsessive materialism and vanity of a Wall Street-driven nightclubbing scene through the story of a serial-killer banker. In the 1990s and beyond, the hip-hop scene has garnered more than its share of notoriety, with shootings a speciality. And yet, some entertainment promoters in recent years have worried that New York was becoming too safe and sanitised to have a really vibrant nightclub scene. But that suggestion never seemed to have a lot of credibility. It ran in parallel with stories about the epidemic use of the party-drug crystal meth, particularly in the gay community. Recently, several high-profile crimes have shown that nightlife here can be a question of life or death. In February, a college student was killed after she left a bar in the trendy Nolita area of Lower Manhattan. An unlicensed bouncer from the bar has been charged with her murder. Last month, an 18-year-old was killed after she left a West Side club. She was three years under the legal drinking age. Between those two grisly crimes, a bouncer at another West Side club shot four patrons, killing one, in May. Three incidents may not make a trend. But press pictures of underage drinkers being sick outside clubs have fuelled demands for a crackdown. There was already momentum in that direction because of increasing complaints from residents about late-night noise. Under pressure from community groups, authorities have tightened liquor-licensing rules. In some areas, a new licence won't be issued unless the proposed business gets more than 150 supporting signatures from residents. The city council passed a slew of bills last week, requiring bars to install ID scanning machines and surveillance cameras and, in some cases, pay for extra policemen. Those who hire unlicensed bouncers will face large fines. But you can be sure that New York's nightclub scene will find new ways to shock and surprise. The industry generates US$1 billion of tax revenue annually: there will always be ways for sexy 18-year-olds to slip under the velvet rope. And sometimes there won't even be a rope: some bolder entrepreneurs are already running underground bars in their own homes - no ID machines there. It isn't called the city that never sleeps for nothing.