Legal Question in Civil Rights Law in Virginia

Re: civil law

You've got the terms for this legal document slightly

askew, i.e., rather than a contract not to sue you, what you're looking for is more likely something akin to a release of liability in which the four-wheeler would agree to hold you harmless for any injuries which he might incur from his four wheeling activities on your land.

And, yes, if this release of liability is properly prepared and voluntarily signed by the parties, it should "hold up in court".