... because an employee at Canada Posts's Mississauga depot keeps stealing all of their rental shipments.
http://lensrentalscanada.com/index.html
An inquiry from a renter got this response:
They're using Purolator for anything that's already been booked but it's tough to run a rental business with no lenses."We are currently halting all shipments with Canada Post as someone at the depot in Mississauga is stealing our boxes."