Kurt Cobain Mustang A electric guitar pickup is essentially much like an energetic microphone coil. For decades, active microphones have now been wired with the voice coil attached to the principal of the microphone's transformer, and not referenced to ground (‘floating'). The microphone's case is typically attached to the wire guard, which is attached to the mike amplifier's ground (see Rane's site for more discussion).
By and large, vibrant microphones are extremely quiet devices consequently of the mix of transformer isolation and healthy, hanging transmission lines during, in addition to protected, humbucking coils.
So why don't you guitars? Guitars are notoriously affected by noise. Humbucking pickups are only an incomplete (though important!) solution. The obvious answer would be to float the guitar collection to a healthy production, as being a microphone. A similar idea was printed that 2001 patent software such as Kurt Cobain Mustang?