I've been doing garbage overload myself more than once, but when you learn about tires - they can carry up to 5x rated load if you are just rolling.
It is the heat that kills the tire bond and that is why dual tires are derated as cooling is limited.
Bottom line, comparing slow driving for few miles to dump site v/s thousands miles with CC set to 65mph is not going to cut.
Other factor are consequences.
I did not worry too much about blown tire at 45 mph when I have 2 feet high load of gravel on my truck.
Blown tire at 65 mph with camper higher than 12' is different story.
