A Halifax parent angry at work-to-rule has sent an invoice to the Nova Scotia Teachers Union asking for $40 in school-trip cancellation costs — and an acknowledgement of the "priceless" cost of disappointment and lost opportunities for students.

Gail MacDougall has two children at Halifax's Citadel High School: Emma in Grade 10 and Sean in Grade 12. Both have been affected by the teachers' work-to-rule job action, but it was the cancellation of Emma's trip to Cambridge, Mass., to take part in the Harvard Model United Nations that led to the invoice, which was sent Tuesday.

MacDougall had known since the Christmas holidays that the trip was off, but didn't learn until Tuesday morning that each family was losing about $40 of their trip deposit.

The invoice MacDougall sent to the Nova Scotia Teachers Union. (Gail MacDougall)

So she sent an invoice to the union asking for the $40 back, with an extra line declaring "punitive loss — disappointment and loss of opportunity" with a value of "priceless."

The invoice also included the message: "Shame on all of you!"

'Double standard'

MacDougall sent an accompanying email, which she also addressed to local media, noting the model UN trip was cancelled but not teachers' travel for professional development.

"This double standard is not lost on parents or our children," she wrote.

MacDougall told CBC News she felt it was important to hold the NSTU accountable.

"The lost opportunity and development for these young adults is significant," she said. "Particularly for those ... who are graduating. They would have used that for scholarship applications. They would have used it for summer job applications. And now that opportunity is lost."

The union did not respond to a request for comment.

NSTU the problem, MacDougall says

MacDougall said her daughter is anxious and disappointed to have put the work in on UN position papers she never had the opportunity to present.

Sean and Emma MacDougall have both been adversely affected by the teachers' work-to-rule in Nova Scotia, says their mother. (Submitted by Gail MacDougall)

The job action also hurts her son's scholarship applications, as he can't get the usual support from teachers or his football coach, she said.

MacDougall said her issue is more with the union than with individual teachers.

"I think if you've negotiated three contracts that your membership is unlikely to support then it's more of an issue between the teachers and their union," she said.

She believes the NSTU has cherry-picked what actions are included in work-to-rule.

"If the trips are out for the kids," she said, "the trips ought to have been out for the teachers."