The rent anybody pays to occupy a space has nothing to do with the issue of "donations" above and beyond rent. Renting a space is a matter of contract law. I have not found any statute in Missouri that protects RV owners in an RV park.
A common lament. But if the property does get sold and the new owner wants to change it's use they will eventually have to figure out a way to relocate unless they have a written space lease contract which, I am guessing, nobody has.
Easy to accuse. Harder to prove.
In Missouri "Fraud has nine elements: (1) a representation; (2) its falsity; (3) its materiality; (4) the speaker’s knowledge of its falsity or ignorance of its truth; (5) the speaker’s intent that it should be acted on by the person and in the manner reasonably contemplated; (6) the hearer’s ignorance of the falsity of the representation; (7) the hearer’s reliance on the representation being true; (8) the hearer’s right to rely thereon; and (9) the hearer’s consequent and proximately caused injury.
Stander v. Szabados, 407 S.W.3d 73, 81 (Mo. Ct. App. 2013)."
Fraud & Statute of Limitations - St Louis Attorney (elsterlaw.com)
You can "say" that all of the elements apply but a court will need "evidence." And you will need a lawyer to present it properly.
There is also a statute of limitations. Read about it at the same link. It's complicated.
There is also a statute of limitations for criminal fraud prosecution.
Missouri Criminal Statute of Limitations Laws - FindLaw
So, when did everybody figure out that there were being scammed and when did they stop making donations?