On an only partially related note, I recall a story from some years back. A person picked up a package off their porch and took it in their house. I can't remember if they even opened it. Soon cops shows up at their door to arrest him and seize the package. It was mailed from Mexico with a hand written label and the post office realized it was drugs. The cops decided to deliver it and arrest the owner. Seems taking it inside means you took possession. I can't remember what the resolution was. There was speculation that it was intended to be intercepted by someone else.
I guess it pays to double check. Most packages shipped to you have printed labels along with all the USPS / UPS / Fedex labels. Now if someone had that and the correct printed address, I don't know how you spot that.
I guess if an unknown box gets dropped off at your door, you should shoot some holes through it just to be sure (from a distance).