As a safety trainer, in Ontario, as well, I prefer that my students turn their upper torso 180 degrees. You cannot stop the company from installing mirrors however one can try their best to not solely depend on them for rearward vision. The mirrors' peripheral vision is limited.

I have a client that many years ago installed mirrors on their sit-down because the operator was too large to turn around. He was a great forklift operator, wise, efficient and timely with minimal bad habits, but just too large to turn around.