"An important thing to remember is that UNDERINFLATION is bad, where over inflation only causes minor issues! In other words, pay attention that you have ENOUGH pressure in your tires, but don't be paranoid about having too much."
I think this is so/so advice for trailer tires, but over inflation can affect traction, ride quality, and stability. A FW or TT with a limited contact patch can get squirrely, skid while breaking, bounce out of control etc. Over inflation on a MH or PV could be very dangerous.
The proper way to set tire PSI is to follow the tire manufacturers instructions. Weigh the rig loaded for travel and set the PSI accordingly. While I agree that when in doubt set to max, it still isn't the proper or safest way to set PSI.
The max on the sidewall of my FW tires is significantly higher than what the recommended psi is loaded for travel.
