Humbuckers without rings just look cheap. (Hey, we can save about 17c in production cost per unit if we leave these off!)
Humbuckers on a strat look terrible. (Ain't no strat no more, sonny!)
But humbuckers with rings on a strat is just sacrilege. (Iron Maiden. Says it all, really.)
Real musicians see the instrument for what it is; a vehicle for conveying music. They will modify the instrument, add things to it, strip things away, and decorate it to suit their fancy because they know that the piece of wood and plastic and magnets and wire isn't the thing that's sacred about it. It's a divining rod for channeling forces from another dimension. That's when the sacred part comes in.