My opinion is that if you leave your bike alone there is a chance something will get stolen or damaged. The bb sounds like a pretty good idea because.... most bike thieves are opportunists. Sure they would come back with the right tools but for what? A 100 dollar saddle they could sell for maybe 1/2 it's value (if it's in new condition). That's assuming they know which is the 100 dollar saddle. I think they would just go find another target. Most people determined and smart enough to go through the motions you guys are talking about don't steal bikes. They steal things like motorcycles and laptops. If they are bike thieves and they are going to make sure they have the right tools.... They will take the whole bike (bolt cutters seem faster than key wrenches anyways).

Best way to not get your saddle stolen? Park it next to the 1000 dollar road bike with the cable lock.