It is puzzling at best to watch the process.
Places like Yosemite have a lot of visitors from overseas in rental RV's, I cringe as the sewer and fresh water hose is thrown into the same compartment. They typically are fast however sanitary can be in question. I take it that not much procedure discussion is held at time of rental pickup.
Also Yosemite has side by side dumps with what should be 2 lines. Why some choose to select the middle line is besides me. Last month I watched a couple argue their middle line strategy with the campground host while the result of his strategy needed only one more truck/trailer for gridlock, no one could move at that point.