The group has sent an ominously worded email to more than 100 people who bought tickets to the June 7-10 Grand Prix weekend in Montreal, warning that their visit to Montreal could be disrupted by violent acts.
"If you intend to use a car, know that your road may be barricaded," reads a document described as a 'Notice to Grand Prix Visitors.'
"If you want to stay in a hotel, know that we may enter it. If you seek to withdraw money from a bank, know that the shattering glass may sting. If you plan on watching a race, know that your view may be obscured, not by exhaust fumes but by the smoke of the fires we set. Know that the evacuation order may not come fast enough."
That was only the latest in a series of web attacks that initially targeted government-related websites under a campaign dubbed Operation Quebec, in response to an emergency law that limits demonstrations.
At first, hackers managed to disable more than a dozen websites, including the sites of the Education Department, the Quebec Liberal party and the Montreal police force.
Now the circle appears to be broadening. In addition to the Formula One spectators having their information published, footage was released Wednesday from an exclusive birthday party held for a member of the powerful Desmarais family.
The 2008 bash was attended by Quebec Premier Jean Charest, as well as former U.S. president George H.W. Bush and former prime ministers Jean Chretien and Brian Mulroney.
"There is a joint investigation ongoing right now into all the threats from the Anonymous network," said Ian Lafreniere, a spokesman for the Montreal police.
"The Grand Prix is part of this investigation. We know threats were made. There were other government sites that were attacked as well."
As Quebec's student protest approaches its fourth month, some groups taking part in the movement have adopted tactics aimed at disrupting Montreal's economy.
The Grand Prix, which attracts well-heeled fans from across North America and Europe, is among the most lucrative periods for the city's tourist industry. It is now being singled out by activists.
"Beginning on June 7th and running through race day on June 10th, Anonymous will take down all the F1 websites, dump the servers and databases — and wreck anything else F1-related we can find on the Internet," Anonymous said in news release Monday.
It added that: "We highly suggest that you join the boycott of the F1 in Montreal and we certainly recommend that you NOT purchase any tickets or F1 merchandise online."
Members of the collective have since managed to hack into a website selling tickets to the June 10 race — dumping names, phone numbers, email addresses, the type of ticket and the amount spent online.
In addition to the warnings by Anonymous, an anti-capitalist group known as CLAC has promised to hold disruptive demonstrations in the week leading up to the race.
The largest student association involved in the strike, the C.L.A.S.S.E., has also invoked the possibility of using the Grand Prix as a "platform" to to apply pressure on the government.
After talks broke down between students and the government on Thursday, Charest labelled the C.L.A.S.S.E. tactic as a "threat to all Quebecers."
Many of those who had their information hacked say they are still determined to come to Montreal. They will, however, take extra precautions.
"I'm still coming but I'll probably be a lot more vigilant,'' said Colin Chariandy, a Toronto engineer who plans to stay well outside the downtown area to avoid any unrest.
''I won't be as relaxed. Hopefully there will be enough security systems — people, cops, etcetera — to make sure the people coming to this public venue are going to be safe. I really hope that that is the case."
According to a member of the collective who sent an email to The Canadian Press through the Twitter site, it was a group known as the People's Liberation Front that conducted the actual hacking operation under the Anonymous umbrella.
Emergency legislation passed earlier this month by the Quebec government was aimed at calming occasionally violent demonstrations by striking students.
Several provisions of the law, however, have drawn criticism from legal experts and human-rights activists.
Most recently, independent experts affiliated with the United Nations criticized what they called the law's "disproportionate" measures, which they warned could be "misused to restrict the legitimate right to freedom of peaceful assembly."
-with files from Pierre Saint-Arnaud.