As for the sporks, I'm not sure it's a liability issue so much as a cost issue — I assume that the disposable spork is cheaper than the labor needed to wash real silverware, and cheaper even than a disposable knife and fork.
This community «lending library» allows neighbors to borrow plates, glasses, forks, knives, linens, cookware and just about anything else they might need to throw a party that would otherwise involve purchasing disposables.