Abstract: The invention relates to a method of tamper proofing a transport vessel such as a railroad car, a cargo truck or an ocean container. The transport vessel has a portion, such as an opening or a fitting, with multiple locations at risk of tampering. The portion of the transport vessel is covered with a pliable cover to cover the multiple locations. The cover is then sealed over the portion with a tamper proof seal in a manner effective to prevent removal of the cover, and to prevent access to the locations without tampering with the seal or the cover.