The southern Alberta man did not appear in Lethbridge provincial court Monday, but pleaded guilty through his lawyer to public mischief.
Friends and family became worried when Robillard, 25, did not turn up for work Jan. 31 at a Scotiabank in nearby Picture Butte.
His car with a smashed window was later discovered running in an industrial area near the Calgary airport. His keys, wallet and phone, along with a pack of cigarettes, had been left behind. Robillard doesn't smoke.
Investigators received an early-morning phone call a few days later from Robillard and found him at a Calgary hotel.
Lethbridge police said his actions were prompted by a significant financial loss.
"The abduction was subsequently staged to make it appear as though he had been extorted in order to account for that loss,'' Ian Sanderson, acting inspector for the Lethbridge police criminal investigation division, said at a news conference in March.
Robillard is a married father of a baby less than a year old.
The police service has also said the investigation into Robillard's disappearance took a lot of resources, cost tens of thousands of dollars and took attention away from more serious crimes.
He is to be back in court for sentencing June 27.
Robillard is not the first person from Lethbridge to be involved in a strange disappearance. A decade ago, a city alderwoman named Dar Heatherington made international headlines for faking her disappearance.
The married mother vanished while in Montana on city business and was found three days later in Las Vegas. She claimed she had been drugged and abducted, but later recanted her story and was convicted of public mischief.
She was also found guilty of inventing a stalker. Following a feud with her colleagues about keeping her job, she resigned from city council.
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