In Nova Scotia the plates belong to the person and not the vehicle. So there might have been a legitimate reason for not having the plates on the new vehicle yet.
"Nova Scotia Licence Plates are assigned to the
applicant, not to the vehicle itself. So, when you get a different vehicle, you can take your licence plate off the old vehicle and put it on the new vehicle. (However, within 30 days, you have to get a new
Certificate of Registration and a new
Vehicle Permit from the Registry of Motor Vehicles."