Seems like a moot point is being argued. This is no different than a auto-transfer switch in a stick and brick house. You loose shore power, and an auto-start generator starts, when it comes up on power the TS goes to the generator. This protects utility workers from electrocution when residents have a emergency generator. The two sources do not come together at any time. Unplugging shore power before starting your generator, is kind of like changing your oil before putting you MH in storage. The people doing the work, or selling you the oil like it, but what does it buy you?