ClearDrift. I would have to disagree. The only part of a spinner that actually rotates, is the blade. The body components remain stationary. So adding a swivel is just one more connection point, that eats up the "feel" of the hardware, and the riverbed. But they still fish with swivels... I just like to feel everything that is happening at that treble!
Russell, I just tie mine straight to main. But I do know a spinner killer who runs braid, and 6 foot, mono shock leaders. He doesn't use a swivel though. Just a nail/blood, or double overhand knot to attach the two lines.