good Samaritans still exist in Sydney as Prankster found out the hard way

The trio who call themselves 'Reckless Youth', comprises of Sydneysiders Daniel Maran, George Proestos and Robert Milazzo.

Mr Maran told ninemsn that the group wanted to carry out a "social experiment" and decided to role-play a terrifying robbery that involved one member 'pretending' to rob another as he withdrew cash from an ATM.

"We wanted to see how many people would actually do something if they witnessed a robbery right in front of them. We also thought the reactions would be entertaining," said Mr Maran.

Wearing a hoodie and a scarf, Mr Proestos sneaks up on his unsuspecting victim played by Mr Maran, and wrestles him to the ground before screaming, "Give me all your money".

A number of witnesses step in to help pull Mr Proestos off Mr Maran, including a man who ends up punching Mr Proestos square in the nose leaving him with a gaping wound.

"He [George] needed seven stitches to close-up the wound and he broke it in three places," Mr Maran told ninemsn.

"We assumed that the person who punched him was wearing a ring. He may still need surgery."

Despite several witnesses appearing visibly distressed by the prank, the group says that was "never their intention".

"Everything we do is for entertainment. Usually as soon as we let people know it's just a prank they are fine with it," said Mr Maran who also defended claims that their actions edged into illegal territory.

"We don't actually do things that are illegal. The biggest charge that we could be slapped with is probably public nuisance and other misdemeanour charges," he said.

NSW Police have been approached to comment.