The mail person should deliver it to the correct address on the envelope unless he knows that the name is a current or expired forward. How does he know if someone may visiting even if he knows the current names? If he is the regular mailman AND he delivers two blocks away, he recognize the name and he may deliver it to the right address. Agreed, the people it was delivered to have no obligation to put it back out, even though it is the right thing to do. Also, the USPS has fulfilled their obligation.