lucky and smart you to never ever been in the wrong place at the right time - or vice -versa.
I had a few close calls in Boston, and while travelling, I do avoid night photography and wandering around if I am alone, or outside fairly busy/crowded areas
Truth is, most gear get stolen from inside cars or homes. Another percentage is sort of found and never returned, which is technically theft - I think it goes along the lines of any item/object valued more than $100 found, you have the obligation to try to return it to the rightfull owner, or an official entity that can do such.
Don't quote me on this, but I am not too far away from the truth.
Now, go find yourself at night, taking pictures alone in a city street, chances are that you are going to get robbed, if you insist flashing around your big camera. and lens...
Common sense will go a longer way than any lens and camera cammo