The Australian Rugby Union has used a few locations for its leg of the rugby Sevens World Series, with Brisbane, Adelaide and the Gold Coast all trying to replicate the fun and buzz and “brand” of Hong Kong’s famous rugby sevens festival. And with the success of the rugby action in Sydney, it seems they have found a home. Because, for whatever reason, the Sydney Sevens went off.

We’re on a full lap of the lower bowl of the second-finest purpose-built rectangular sports stadium in Australia, Allianz Stadium (Brisbane’s Suncorp Stadium is the best) and take in dinosaurs, Minions, Superman, Batman, Spiderman, chickens, cave-people, the Pope, William Wallace, Jesus, Cleopatra, Zorro, Darth Vader, stormtroopers and what appears a fair portion of Fiji. For the fans, the Sydney Sevens, like all the World Series events, is as much about playing dress-ups and drinking beer as it is about the rugby.

Like Test match cricket and a day at the races, it’s a social event. It’s also a flow-on from kids playing pretends. Young adults enjoy dressing up and drinking beer. And the Sydney Sevens is awash with plastic cups of mid-strength lager and young adults dancing about dressed as chickens.

I head to a hospitality box and hook up with friends from Canberra Royals RFC, dressed to a man in the black hats and capes of Zorro. It’s 6pm and hot like the jungle. One of our number, Mick, has been to the Hong Kong Sevens several times and says authorities effectively rope off the South Stand there and let everyone within “do what they like”. He offers that as a reason the Wellington Sevens has lost its lustre.

On the field Fiji score a super try against Argentina, going the full length of the field, in an entertaining game. And the flag of their country waves a lot. It’s interesting to watch the players’ human movement. The Argentines run straight lines with a step, looking to carve incisions with laser-beam intent. The Fijians seem to float about and jag off a pin, stuttering with a jerky sort of running that begets hot action. They rip off floating passes and kicks that don’t seem obvious. Why an archipelago of 332 islands and 900,000 humans is so very good at sevens rugby is an anthropological study for another time. But good they are, Fiji. And everywhere, in fine voice.

A battalion of stormtroopers enjoy the atmosphere at Allianz Stadium. Photograph: Cameron Spencer/Getty Images

Sevens first came to notice for many in Hong Kong in 1990, when Fiji won the final against New Zealand by playing some of the most outlandish rugby ever played. The Kiwis of the time were effectively half their champion Test team: John Schuster, John Gallagher, the great Eric Rush, the inimitable Zin Zan Brook, my favourite All Black. But Fiji, led by 20-year-old player-of-the-tournament and legend Waisele Serevi, knocked over the Kiwis with a try that should be frozen in time – see the ball float over the top to be tipped on to another man who shoots it out through his legs to a speed man who burns the Blacks with the extended gait of a galloping quarter-horse. Top stuff.

There is plenty of entertainment out here at Allianz, as 70,000 people over two days would attest. At any one time it doesn’t look like there are 35,000 in the stadium, at least not on the Saturday I’m there. But still, ARU suits will be stoked with the success of the tournament.

Rugby in Australia, you see, outside of well-attended Test matches, is the poor cousin of the rival football codes. The A-League runs in the summer, while the NRL and AFL rule in terms of TV numbers, really the sole arbiter of sports dominance in the land. So for the ARU to fill Allianz two days in a row and notch impressive television numbers while the NRL has a Nines tournament in Auckland and the AFL has nothing at all, well, they’ll be patting themselves all over each others backs in mahogany row. Especially given the two final games of each day is Australia versus New Zealand.

And then a samosa hits me in the face. Yes! How about that? Someone from another hospitality box, I never work out where, flings one of the hot little pastries, and socks me fair in the face. And it’s quite a shock. And I am briefly confused and angered.

There’s a break for dinner and the Veronicas belt out some tunes. They’re very good and so our troupe of Zorros dance about with airline pilots, and you think: every generation has done this, or something like it. They did it in Happy Days – Richie Cunningham and Ralph Malph dressed up for a party at high school. Richie’s dad, Howard, would dress up in a leopard-print fez and head to the Leopard Lodge. True story.

Karaoke plays on the big screen. Tom Jones belts out I-yi-yi, Delilah as Japan play Wales and nobody cares. The US run out to play England. Both teams huddle. Flags of both countries flap about. And the footy action is good. There’s a dummy by England’s Alex Gray, who streets the field. Tom Mitchell, England’s captain, does some strong running, hard charges at speed. Lenny Kravitz belts out over the intercom.

USA speedster Perry Baker sets sail and hares off for the try-line, running over. But he plants a foot on the dead-ball line and stuffs it up. And England win, later falling to Australia in the quarter-final. The Zorros from Canberra are advised they’re not allowed to take “selfie” photos with staff members because … there is a rule they cannot. Because security runs the world, or at least Sydney.

On the field a streaker tears out and about, and dozens of bright-bibbed security guards studiously face the other way, trained as they are to focus on the crowd, the poor drones. Eventually the man is collared by police, and thrown out along with 81 other people. If those numbers were thrown out of an A-league game there’d be tabloid terror. But it’s rugby, so there isn’t.

The last game of Saturday night is Australia versus New Zealand, and a bearded hipster-looking fellow on the big screen is dancing up a storm to John Farnham’s “You’re the Voice”, making a motion as if drawing the whole song into his very being. Mick says he was on the big screen earlier in the day, on “Oblivious Cam”, pretending to read the Australian Financial Review. Would a young adult dressed in a black tie and jacket bring the business pages to the rugby? They would not. Is the hipster something of a plant, an actor? We may never know. But good luck to him.

And as we file out with the masses I think, good luck to the ARU. For all the entertainment of the rugby and the appreciation of the action and skill, if there wasn’t the party atmosphere, no-one bar Fijians and bearded plants would attend. But that’s OK. Because Sevens has found a home in Sydney town.