Find the deepest pockets...If there is a civil action the lawyers will go after anyone and any entity that can be connected. The deeper the pockets the more attractive the target.
If the pilot was a minor his parents are financially liable for his actions. How deep are their pockets?
There was an ordinance prohibiting flying RC aircraft in that park, but no signage to that effect. The accident moved the the city to post such signs, after the fact, closing the barn doors after the horses escaped. How deep are the city's pockets? (Sure, ignorance of the law is not a legal defense, but the city has already decided not to press charges against the pilot, not even a citation for violating (albeit unposted) park rules. Dumb, from every perspective.
End result? One or more insurance companies will work out deal that, through premiums, we will all fund.
"Pay attention...lest the ground rise up and smite thee."