Common assumptions about bolt seals:

• Deter against the unauthorized opening of container doors.
• Combine strong physical protection with tamper evidence.

Yet, bolt seals and related components can be easily compromised:

• Most bolt seals can be defeated using a technique called “spinning” - and then resealed.
• Bolt seals applied only to the door-rod handles can be circumvented and the doors opened and re-closed, without any apparent evident of tampering.

Any bolt seal can be defeated.

Bolt seals can be prepared in advance by employees, organized crime, etc., to have threads.  Threads allow a perpetrator to unscrew a bolt seal and easily screw it back together.  The same employee then passes the container # to a partner to quickly and efficiently steal cargo.  “Spinners” can also use this trick to open cargo doors.  Since its shank is hidden, tampering is not visible from the outside.
Use of a bolt seal is not secure and even dangerous (false sense of security).

Parts Are Interchangeable

This picture displays a few of the many styles, shapes and colors of bolt seals on the market.  The other photos at bottom show how two parts (pin and locking head) from different bolts produced by different manufacturers, can be substituted without detection.

The Bill of Lading lists only one seal number with no further details such as if the bolt is double-numbered, if the pin is the same color as the locking head, or if it is painted or galvanized. 

It is easy to cut the pin, drill out the pin from the locking head, and replace it with any new pin without a number.

Any seal with multiple parts is easy to tamper.