he cable-lock design adds an extra element to bicycle theft prevention by incorporating cores of compressed air and liquid running through its body. When a bolt-cutter wielding would-be thief cuts the cable, the liquid is sprayed out making the bike, the perpetrator, their tools and the crime scene easily identifiable.Even if the thief does get the dye off, he (or she, let's be equal opportunity crime busters here!) won't be able to remove the ultra violet dye which makes him light up like a Christmas tree under a black light.
I am all for making it harder to steal and fence bikes and the Smartlock is one step in the right direction.
More info on Smartlock.