Canadian border guard sees a person who is a criminal (once a criminal conviction is issued, one remains a criminal as this is a permenant record, forever).
Than prescription meds without the owner present are found.
Than an undeclared weapon (pepper spray) is found.
The Canadian border guard sees undesirable people in the vehicle and probably thinks, "What else are these folks trying to hide or what else are these folks not telling the "whole" truth about.
There are two sides to every story and I will bet the Canadian border guards side of this story has a different "cant".
Lakeside