Required or not, you read every now and then of one breaking loose from the MH. Other than not having one will probably get you sued in any state, but I would be more bothered if mine broke loose and killed, injured, or maimed someone. Knowing that a simple device could stop it as a last resort, I would rather spend the few bucks and have one, than be cheap and have to explain to folks why I didn't spend it. It is a personal choice, but what if it were you or a family member staring down a loose toad because someone chose not to?