I've been reading some articles on shielding and I'm scratching my head at a couple of things. First, if shielding is necessary, why are so many "good" basses not shielded at the factory? It looks like a pain in the *** to do yourself, so why would the guitar companies sell instruments that are unshielded? Second, on the Delano pickups website, they mention that their pickups are shielded, as though it's a feature. Is it to be expected that any quality pickup comes shielded? If not, why not?