Well Gang,
This is all about COMMON SENSE! It doesn't take a rocket scientist to judge just how much pressure is needed for a given job or, just how close or far away from a surface you need to be to accomplish a purpose. You can use a 3000 psi pressure washer on any surface you'd like as long as you don't get close enough to do damage. It's all about accomplishing your goal without issues. As you can see and read here, some do it and some are really advocates against it.
And yes, just about 100% of the detail crews, at any campground/RV park that allows them, use a PRESSURE WASHER, with few exceptions. If you watch them, they don't get close to rubber seals in windows, graphics, and anything else that can possibly either let water infiltrate, or be damaged by the higher pressure. The MAIN reason that they use them is water control. The can do a good job of rinsing, getting all the soap solution off without creating the Mississippi river in the middle of the camp ground.
And that's the primary reason that most campgrounds will NOT allow for RV owners to wash their own rig. Many of you are smart enough to use a nozzle that controls "on-off" to keep from flooding the entire campground but, some, will just let the hose flow while they soap down their machine.
Anyway, a pressure washer is perfectly safe, as long as the user is wise in its use.
Scott
Scott and Karla SDFD RETIRED2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad
2008 Caliente Red LVL II GL 1800 Goldwing KI60ND