Again, TRAILER tires are meant to be run at the maximum rated pressure. The OP is not referring to passenger vehicle tires. Please don't confuse passenger tires with ST tires. Trailer tires have a stiffer sidewall and are meant to be run at the maximum pressure. The stiffer sidewall not only accommodates higher pressures but helps prevent trailer sway. If you run ST tires under inflated they will heat up more and eventually fail prematurely.
Passenger tires are a different ball game. I run higher pressure, close to the max, in my '07 F-150 if I am hauling a load of stone or something else really heavy, but other than that I run them at around the recommended PSI.