I believe that I have bought the world's most useless lock.

It is a Brookstone cable lock to use on zippered bags. It is a TSA-approved lock, meaning that they can open it with keys they have.

Okay, that is unavoidable given the fact that the TSA, in most airports, inspects your checked luggage out of your sight.

However, this particular lock has two other problems:

1. The cable is so thin that I suspect that a strong nail clipper could cut through it.

2. The combination is changed by setting the combination to 0 0 0, depressing a button, and putting in the new combination.

Note: You do not have to know what the old combination was. Anyone, therefore, can change the combination on your lock to whatever he wants and then proceed to open it.

Ah well, at least you don't have to worry about forgetting your combination and not being able to get into your luggage. Just set a new one.