EMGs are internally grounded but aside from that, the bridge needs to be grounded in a normal wiring setup. That's basic and required by all wiring codes and standards.
It's true, people have (rarely) been electrocuted by becoming part of a live circuit in a club with faulty wiring. The bridge didn't cause it. If you suspect a problem, the solution is to check polarity and grounding before you plug in. Not to deliberately make your bass' circuit faulty.