In all suits or actions (other than those arising under section
1592 of this title) brought for the forfeiture of any vessel, vehicle, aircraft, merchandise, or baggage seized under the provisions of any law relating to the collection of duties on imports or tonnage, where the property is claimed by any person, the burden of proof shall lie upon such claimant; and in all suits or actions brought for the recovery of the value of any vessel, vehicle, aircraft, merchandise, or baggage, because of violation of any such law, the burden of proof shall be upon the defendant: Provided, That probable cause shall be first shown for the institution of such suit or action, to be judged of by the court, subject to the following rules of proof: