Based on what I've seen of the court documents, the 8th Circuit Court of Appeals will reverse Marc's conviction(s) in strong language.
If they don't, here is what will happen regularly; federal judges will place a jury instruction in all cases where a federal employee is accused of behavior similar to that of Duke Bourne (the BIA guy in all the posts below). That jury instruction will read:
No federal employee can be considered a trespasser as a matter of law. Anything a federal employee does while committing what would be trespass for you shall be considered in the same light as if it were committed by the actual property owner. Come to think of it, a government employee would be the equivalent of the actual property owner in a strong sense.