The 32A 5-pin plug will work with 32A 5-pin sockets at showgrounds, but there's a wide variety of sockets out there. Apart from different maximum current (eg. there's also 20A and 10A 5-pin sockets, that physically won't accept the 32A plug), there's also sometimes 4-pin three phase sockets that don't have a neutral, and those won't work for charging the car (the plug doesn't fit, and the car needs a neutral link anyway).
Separate to this, the car checks for a neutral-earth tie so it won't work on some generator setups - this is regardless of which plug you're using.
We have some of those at work too, 32A 5 pin and 20A 5 or 4 pin. As you say, they are not interchangeable.
Electric forklift had a 4 pin 20A.
EVChargers do a kit which has different adapters for all the different combinations, but it starts getting a bit $$ if you get all of them, and they are pretty heavy due to good industrial materials so extra weight to cart around.
I looked on plugshare and noted places i might go to one day and figured id be ok with the following;
1. Charge at home or work when no one is looking.
2. Use Superchargers or Chargefox/Evie mostly
3. Use destination charger at accomodation.
4. Carry a type 2 cable for some of the untethered outlets.
5. Use the UMC with the 10/15/32a tails as needed if nothing else available.
I dont caravan but i heard there are some special caravan plug/sockets also which were meant to dissuade people from plugging anything other than caravans in to powered sites, but you could just daisy chain from the slower outlet in the caraven, which is probably more dangerous hahaa
I dont panic where service stations are currently, and see the availability of power more ubundent with a bit of planning