The extreme measure of taking the case to court, which the girl's lawyer defended as a necessary move to ensure the child was not denied a significant rite of passage, was upheld by the judge in a surprise ruling last week.
"This was something that would never happen again in the child's life," said Lucie Fortin, the lawyer for the girl, who cannot be named.
"And for me that was really important, because it was the end of elementary school, it was the end of a stage in her life."
Ms. Fortin insists that while court was a last resort, the situation called for it: "This was not a question of going to the movies or not, or going online or not -- because obviously, I wouldn't have intervened in that," she said.
Critics of the decision last week by a Quebec Superior Court that ruled in favour of Ms. Fortin's young client suggest that such a ruling opens the way for equally implausible scenarios such as children taking their parents to court for such things as being denied access to television or use of the Internet --and winning.
"As a lawyer and as a parent, I think it's state interference where the court shouldn't be interfering," said Ottawa lawyer Fred Cogan. "I've got six kids. I certainly wouldn't want a judge watching over everything that I do, and I wouldn't want my kids being able to run to the judge."
The lawyer acting for the father in this case, who also cannot be named, said she is going to appeal the decision.
"The judge said that this was an exception, but the exception was to go on a field trip!" said lawyer Kim Beaudoin. "What will be too much punishment? Not going to a dance? 'I want my boyfriend to sleep at my house and my parents aren't letting me?' 'I want to use [the] Internet and my parents aren't letting me?' Where will it stop?"
The ruling to allow the field trip went against the wishes of her father -- who has legal custody of her -- but was in keeping with her mother's wishes.
And while the case is raising some eyebrows, a tangled, behind-the-scenes custody battle must be taken into account, said Montreal family law lawyer Miriam Grassby.
"It's a very different situation than a child who might appear to not be happy with the parent's decision and simply say, 'I'm going to go to court and I'm going to get what I want,' " she said. "And if in fact it's been portrayed that way, it's not putting it in its complex context."
While the girl's father has full legal custody, pending a further court decision, the girl has been living with her mother, Ms. Fortin said. But while Ms. Beaudoin says the girl went to live with her mother when her father forbade her from going on the trip, Ms. Fortin contends that she was "kicked out" of her father's house over family tensions.
"In a situation like this where you're in contested custody proceedings, there's often a high level of conflict," Ms. Grassby said. "And one of the reasons that in Quebec children have lawyers named for them is because the parents and the court recognize that in high-conflict situations it gives the child a safe place to first give their opinion, and get advice."
Others say there are few signs Canadian courts are likely to follow the Quebec court judge's lead. "Family court judges are sort of loath and reluctant to enter into the sphere of parental discipline," said Peter Dunning, executive director of the Child Welfare League of Canada.