It is said, “ignorance is no excuse.”
This is often misunderstood. The correct statement is "Ignorance of
the Law is no excuse." Ignorance of the facts
is an excuse, because it negates
mens rea (guilty mind). So if you would have no reason to believe that the contents of the box were anything prohibited in law, then you are innocent of the crime, lacking the required element of
mens rea.
