A magician who broke an elderly woman's wrists by pushing her, and later failed to appear for multiple court commitments, was "brainwashed" by protester groups, a court has heard.
The 67-year-old victim, who was working at the Exhibition Park in Canberra at the time of the assault, fractured three bones and required surgery.
Cameron Robert McKay, 36, faced the ACT Magistrates Court without saying a word on Thursday despite his previously energetic appearances, even once being called an "idiot" by a magistrate.
The NSW man previously pleaded guilty to causing grievous bodily harm and two counts of failing to appear in court after a bail undertaking.
He was handed a three-month jail sentence, which magistrate Ian Temby elected to suspend, and a two-year good behaviour order.
McKay has spent 35 days in custody.
The man's violent offence occurred on the morning of February 10, 2022, at the Exhibition Park, where he was camping after travelling to the territory for the Convoy to Canberra.
McKay had been invited to the camp and asked to "entertain the campers with his magic tricks".
At the request of an organiser, he went searching for a PA system to be delivered to a protest taking place at the High Court.
The offender mistook the "somewhat confusing" instructions about where to find the system and accidentally wound up in a private office.
There, he was met by the victim as he attempted to take the wrong system.
The pair began to argue and the woman tried to physically "usher" McKay out of the building by pushing and pulling, causing him at one stage to stumble backwards into furniture.
"Stop assaulting me," he said to the woman multiple times.
After some further arguing and tussling, McKay pushed the victim "using both hands with enough force that she immediately lost her footing and fell to the ground", agreed facts state.
The court accepted the man believed he was acting in self-defence but said he had also done so out of "frustration".
"His response was not reasonable in the circumstances," the magistrate said.
Legal Aid lawyer Brandon Bodel said his client had acted "beyond what he was allowed to in relation to self-defence".
"At the time he thought he was doing the right thing," Mr Bodel said.
Mr Temby said the man had written his victim a letter from custody in the months following the assault to apologise.
"Your actions put me in a state of fear however I can't express how awful I feel about my part in the situation that resulted in the injuries you sustained," McKay's letter said.
The woman spent five weeks in arm casts, and required screws and a metal plate in one hand.
A prosecutor said the court could give McKay the benefit of the doubt for his first failure to appear in court following the assault but that he was "absolutely and undoubtedly on notice" before his second.
"He thought he was effectively utilising the law by sending various letters thinking he could be excused from attending court," Mr Bodel said.
A magistrate previously described one of those letters as "gobbledygook".
The lawyer said his client was "particularly influenced" by one protester group who didn't understand the legal system.
The court heard McKay suffered from schizophrenia but had "come a long way" since his offending after seeking treatment.
Mr Temby said McKay's mental impairment did not reduce his moral culpability for the assault.
Mr Bodel said his client was deeply ashamed and the magistrate accepted McKay was "entirely remorseful" for the assault.