I've recently been looking to swap the body of my strat with a lighter one, and have come across a few artist series which don't have a back plate over the tremelo cavity. I'm talking specifically about the Eric Johnson and John Mayer models. Can anyone tell me why they're doing that? Is it just for looks, or is there a certain tonal quality they're going for? I hadn't seen that before (of course I hadn't been looking either). Sorry if this has been covered before - I did a search but no luck.