ive bought books off of amazon before and every time the parcel has arrived without any indication as to what the contents were, although i have always had to sign for them. get to the door first and sign for it yourself otherwise your folks might start asking questions. other options are [a] to have it delivered to one of your [trusted] mates houses or [b] make sure nobodies home at the time of the delivery so that the parcel cant be delivered, quickly get the missed delivery ticket from your letterbox and retrieve the parcel from the post office. regarding option [b] i dont know how the postal service works in the us, but here in england if a parcel cant be delivered they stick a note through your door telling you to pick it up at the post office.