This.If a 40 ft trailer loses a tire, there are three more on that axle, and at least one on that corner. Yeah, it presents a dangerous situation, but not as bad as a vehicle with only four tires, of off-pavement size, losing one in a catastrophic delamination. You don't want that to happen at all.
How many times have you had to dodge the carcass of a delaminated tire on the highway? Too many to count. And a lot of fleets won't use retreads on the front wheels (steering), but just the drive and trailer axles with multiple wheels.
Long ago (about 30 years) I bought a beater used car for my last couple years of college. On a trip home (just a few months after buying it) from SW Va to NJ, the rear driver tire partially delaminated at ~60 mph. The freaky steering combined with a 6" wide strip (about 2' long) of tread slapping the underside of my car a few hundred times a second damn near gave me a heart attack. It flattened my tail pipe, too.
When I got home and took it to a tire shop was when I learned about retreads, which is what the rear tires were. Replaced them right then and there.
After that experience, I'll never use a retread in anything that goes over 20 mph. Your mileage (risk tolerance) may vary.