They definitely confirm that if you deny the pack is yours and refuse to sign they can't pursue charges. They open a package with like 2 keys of heroin, they then send it to local authorities in his area for a controlled delivery. During the initial investigation they also discover the recipient listed has a history of possession of heroin. After all this they go on to say they hope the pack isn't late or look torn into because if he denies the pack they have no case.
They also show the way they look through packs at customs. What they look for, small shit I would have never thought of. Show tons of stealth methods used.