Originally Posted by Yoshi

Nope, not defective. The technique being used to "pick" the lock is called impressioning. A pliable material (in this case the plastic pen) is pushed into the lock and the pins push against the material until an impression is made. This impression then mimics the key.

Just about all tubular locks are susceptible to this sort of attack, provided you can find a piece of pliable material of the right diameter. This isn't terribly hard either - I've seen a video of a guy pick a kensington laptop lock with a roll of toilet paper! He cut out a piece from the cardboard tube that was just the right size.

Impressioning also works on regular locks with flat keys. However it is much more difficult to do and requires special "blank" keys that will fit the ward of the lock. Since tubular locks always have a circular ward it's not as difficult to find a blank that will fit it.

The new Kryptonite locks use disk locks which are extremely difficult to pick and require special tools. The American padlock requires only normal lock picks and is considerably easier to pick, but it does contain several security pins which makes it more difficult to pick than a typical lock.

With all that said, regular locks are rarely ever picked by thieves. Typically lock picking requires skills and tools that a thief wouldn't bother learning as there is usually a faster alternative.