Everyone with 50 amp service should have a hard wired EMS. If you loose neutral on 50 amp service it puts 240 volts across all items in the RV that are plugged it. Having a hardwired one provide better protection than one you plug in at the power pedestal, protecting one for shore cable, is plug on each end and power reel if you have one. Loose neutral and most if not all of your electrical devices get fried. We have a PI HW in both of your RV trailers. HW EMS do not grow legs and walk away.
With the 'little guy' trailer we found that a friend's outside outlet on his garage had reverse polarity and would not power the trailer on. This spring at another friends home on the way back North his garage outlet was old and worn, and PI said no ground available and would not power up the trailer.
Chris