It was supposed to be a mixture of social experiment and prank, filmed in the Sydney CBD for the YouTube generation.
But it backfired on three youths when one boy was reportedly left with a broken nose by one of the prank's victims.
Reckless Youth is a group recently formed by Daniel Maran, aged 19, and George Proestos and Robert Milazzo, both 16.
On Tuesday, they uploaded to YouTube a series of staged ATM robberies in the Sydney CBD, which quickly attracted hundreds of thousands of views.
The purpose of the video, they claim, was “to see who would try and stop a robbery if they witnessed one happening in front of them".
But the venture backfired when one would-be good Samaritan threw a punch that Mr Maran said left one of his collaborators with a broken nose.
Meanwhile, police have warned the trio against repeating their stunt in future.
The video cuts together a series of scenes in which Mr Maran is attempting to withdraw money from an ATM, before one of his friends emerges in a balaclava and screams “give me the money”, at times pulling Mr Maran to the ground.
In each scene, bystanders run forward to assist Mr Maran before the boys laugh and reveal: “It's a prank, it's a prank.”
In the final scene of the video, staged at the MLC Centre in Sydney, George Proestos, as the perpetrator, is attacked by a bystander who punches him in the face, reportedly breaking his nose.
A group of bystanders proceeds to assist the bloody youth, one bringing him paper towels from a nearby restaurant.
Mr Maran said the reaction they have received has been unexpected.
“Every single comment has been negative, saying how stupid we are, how dumb this prank is," Mr Maran said.
“Honestly, I didn't think it would be that negative. I thought we'd get a few people saying this is a silly prank – but literally almost every single comment is a hate comment,” he said.
The response from bystanders when they staged their stunts also surprised him.
“We thought, he'd tackle me, he'd take the wallet and then he'd run away and no one would really do anything – but from the get-go, people were jumping in and stopping it, which is kind of the point of the video, just to see who would jump in, in a robbery situation,” he said.
Mahendra Singh, 35, features in the video and was one such bystander who became involved when he saw a prank robbery on George Street in Sydney's CBD.
“I saw one of the guys taking money from the ATM – and from behind came a hooded guy who just jumped on him. When I saw that, I just pounced on them. I was forcing my elbow on his windpipe, so that he would let go of the wallet, and I was screaming for help and asking people to call the police,” he said.
Mr Singh said he failed to see the humour in the incident.
“The first thing I felt was very angry, and I just felt it was a very silly prank. I was worried that this person could have been hurt or I could have been hurt. I was just furious and I just walked off.”
He said he didn't want to interact with anyone because he felt embarrassed.
A NSW Police spokeswoman said police discouraged people from partaking in any activity that could cause harm to themselves or others.
“Such activities can be highly dangerous and easily misconstrued by members of the public. In some cases, participation may also constitute a criminal offence,” the spokeswoman said.
Mr Maran said the group would refrain from doing anything as risky in future.
However, late on Tuesday night, the group uploaded a new video to their page, titled: “Public fight prank gone wrong (arrested.)”
In the new video George and Mr Maran stage a "fake fight" in public.
The video description reads, “Security ends up breaking the 'fight' up and the police were called. Luckily, one of the security guards kept the camera rolling as they took us down to interrogate us and caught it all on tape.”