As to the original question: with modern electrical systems, for someone to be shocked, there is almost always at least two failures involved: the primary failure of the electrical insulation, and the secondary failure of the safety system.
(Usually, what I have termed a "primary" failure happens after the secondary failure. I call it a primary failure not because of chronology, but because the insulation is the primary safety device. The EGC or breaker or GFCI is the secondary safety device.)
It would initially appear that the EGC is not properly connected in one or more pedestals, and a fault in one RV is backfeeding throughout the CATV shield to the other RVs.
I wouldn't be surprised if the grounding terminal of the receptacle in the pedestal isn't even connected to anything. The wiring is probably a 3-wire bundle either overhead or underground, two hots and a neutral (no ground). The pedestals may be designed with separate neutral and grounding busbars, and the installer didn't jumper (bootleg) the busbars together. If a ground rod was connected, there's no bond to neutral to provide a return path, and if the soil is sufficiently dry, that doesn't provide a good return path, eiter. With no ground wire in the feeders, there is no connection to the service entrance bonding point, or to other pedestals, so the voltage backfeeds throughout the CATV.
If there is a ground rod at each pedestal, but no bond between pedestals, the CATV cable provides a bond through a bonding point (intentional or unintentional) in other RVs.
So you have this condition: hot to chassis fault in RV #1, chassis to CATV shield bond in RV #1, voltage through shield to RV #2 (and 3 and 4), bonding point CATV to chassis in #2, hot skin #2, voltage on EGC of #2 to pedestal, into ground rod at #2. Because the ground rod at #1 pedestal is too high impedance, current flows through CATV shield to ground rod at pedestal #2, accounting for the damage seen in the CATV distribution system.
This shows the importance of having a continuous INTENTIONAL ground path/bond between power distribution points (and appliances such as an RV) to ensure they are at the same potential (as the soil), as well as an INTENTIONAL bond between ground and neutral to provide a controlled return path for fault currents to increase the likelihood of tripping a breaker in the event of an insulation fault.
EDIT: The proper repair is to install a proper EGC from the bonding point at the service entrance to each pedestal, and keep the neutral and ground separate at each pedestal. But if there is no master service entrance -- that is, if each pedestal is considered a service entrance, then bonding the neutral and ground at each pedestal and installing proper ground rods at each pedestal is the way to go. You probably need a ground rod at each pedestal, whether or not neutral and ground are bonded at the pedestal.