I have seen several parks that stated No Electric Heaters. I have also been to a park that charged extra if the RV had an A/C. It didn't matter if you planned on using, if you had it, you got charged extra. We had an A/C, had no need to use it, but since we had to pay extra, we ran the A/C to get our extra $3 worth. Have never returned to that park.
I have never encountered a park that did not allow the use of an A/C. I certainly would not stay anywhere with a rule like that, especially for $50/night.
-Michael
-Michael