There she stood in the frenzied mosh pit, amid flailing arms, flying beads of sweat and the growling ecstasy of the mob, threshing like trawler bycatch. As a teenager in Jakarta, Dea Arida was never allowed to go to hardcore punk gigs, her protective, strict parents considering them dangerous and corrupting. But Australia is a long way from home. Here, for the first time, Dea could immerse herself in the punk band scene. For the first few years, she methodically removed her Blu-Tacked ticket stubs from her bedroom wall each time her parents came to visit. By 2014, when her 14-year-old sister visited, Dea was ready to come out as a hardcore fan. "I took my sister [to the mosh pit] to prove a point to my parents," Dea says. "Gigs here are safe." And Dea's boyfriend came, too. New country, new rules.

As Dea was leaving to study at Melbourne University five years ago, her worried parents showered her with advice. Don't let guys stay over. Maintain your Catholic faith amid Australia's secularism. Avoiding alcohol didn't even need to be said. Dea listened. But she was nursing a secret. "It wasn't something I told my parents, but the liberal nature of Australia was a reason I came," she says. "Here, you don't have to conform to your peers as much. There's a lot of freedom."

Zongyi Fu from China. Credit:Bonnie Savage

International students are our hidden migration boom. More than half a million – most from Asia – live here as temporary Australians while they complete their degrees. Many play it safe, sticking close to friends from the same cultural background. Loneliness and isolation are common. But for the more daring, Australia is a liberal playground: a place without family pressure, with far fewer rules, and where drinking and partying are rites of passage.

"Most international students are from an upper middle-class background," Dea explains. "So they're very sheltered and privileged at home. Here, they are finally free. They can try things not condoned at home. At home, my friends can't go on dates wearing shorts, let alone be alone in a room with a boy. Here, it's much more casual. People might even experiment with their sexuality. But then going home is hard."