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Theoretically, another plus for star grounding is the ability to keep your hardware and strings grounded behind a .33 400 volt capacitor. I play through a 54 year old amp when recording... should it fail, the .33 cap should "absorb" the lethal voltage punch.
The only thing the capacitor is doing is blocking DC current flow. It still lets AC through however, but at a certain frequency based on the value of the cap. I usually see this done with a resistor in parallel with the cap.
Now here's the thing about star grounding. It does not stop electrostatic noise as picked up by the single coil pickups, and neither would foil or conductive paint shielding... unless you wrap the pickup in foil or paint!
Star grounding can help to prevent ground loops and eddy currents, as John already mentioned. Shielding your control cavity *may* prevent the wiring from pickup up electrostatic noise, but it will not stop your single coil pickups from picking up hum.
Now the reason you can get a shock is from improper grounding on some amps. The "ground" switch, or improperly wired mains outlets, can cause the chassis of the amp to have live voltage! Especially for older amps without the three pin AC plug. So what happens is you complete the circuit when your grounded strings make contact, through you, to a microphone or someone incorrectly grounded piece of gear. Star grounding will not stop this from happening.
Personally I just disconnect the ground wire from the bridge.