And if the two parties “voluntarily” enter “into a binding arbitration agreement” that says the loser gets his right hand chopped off, is that okay too?
Reductio ad absurdum. See my comment just above about a "little knowledge being a dangerous thing".
You can't be obligated (even voluntarily) in a contract to be party to a crime as a provision of the contract. "Chopping someone's hands off", would be a violation of US criminal law - probably both federal and state laws.
Part of the first part agrees to let party of second part marry 3 daughters of the first part by order of Mullah Ali Ali N Free. There by, Tampa ,Hillsborough, Florida judge that is Coooool!