Think about leaving your bike unlocked in times square, vs. the top of a 7 000 meter mountain in the himalayas.
Which unlocked (unsecure) bike is more likely to be stolen, and ergo has a lower risk attached?
----
Obscurity does not help you when the thief has already found your bike, nor is obscurity very helpful for keeping your bike safe if you happen to live in times square.
But if you live at the top of a himalayan peak, you can be fairly certain you're not going to have your bike stolen.