There are often discussions about 50 amp power and what effect wiring errors might have, including some very recent ones. For anyone who might care, my musings ended up with sketches. Here are some rough sketches of 50 amp power, one wired correctly, and one with one hot and neutral reversed and the effects of that.
The first picture depicts the system when wired correctly. Power company line power can range from 5-7,000 volts and up, 13,800 volts being fairly common for residential. Their individual transformers provide 240 vac power with a transformer center tap that splits that into two separate 120 vac hots. For RV 50 amp power, each of the 120 hots can supply 50 amp power for a total of 12,000 watts of power. 240 vac is in our RVs, but only high end units would typically use anything other than 120 vac.
The first picture shows the two branches of hot with the main 50 amp breaker and sub breakers (15 or 20 amp) for each branch circuit and associated loads. Each branch of 120 vac wired correctly. Example; HOT1 might power A/C1, water heater, microwave, etc. HOT2 might power A/C2, converter, miscellaneous outlets, etc.
The second picture shows the HOT1 wire reversed with the NEUTRAL wire in the shore power receptacle. In this case, the voltage on the HOT1 loads is still 120 vac. The miswire simply reversed hot and neutral. And since this is alternating current (and alternating voltage), functionally the load doesn't really care which wire is hot or neutral. Remember when appliance cords only had two non polarized pins? Some things still do.
But their is a major problem for the HOT2 loads. As the picture shows, the neutral terminal is now connected to HOT1! That means the voltage across the HOT2 loads is 240 vac instead of 120 vac. There is no longer a neutral in that circuit. Not good. Any devices plugged in to that hot would likely be destroyed.
This is where an EMS is great preventing power from passing and damaging the RV. And I would think a surge protector would be able to prevent power from passing also without damaging the surge protector. But one discussion leaves that in question.
Sorry if my little brain takes away from your time.