"I was putting the sandwich inside the Ziploc bag and he said, 'Mom! You can't use a Ziploc bag in my lunch!,' " she told CBC News.
Theoret learned that there was a draw for a teddy bear at her son's kindergarten class, but that if you had a plastic bag in your lunch you weren't eligible.
"The goal was around environment," she said. "However, my boy is six years old so he doesn't understand, or he didn't remember that it was around environment. All he understands is that if he doesn't have a Ziploc bag he won't get the [teddy bear]."
Theoret believes it was a harsh way for their six-year-old to learn about protecting the environment.