Eclipse, JVC, and clarion decks burn out the internal amplifier if you operate them without a direct ground.

Trust me I've had to replace decks because of bad grounds that took the internal amps with them. Good thing is you can just throw a 4channel amp on the RCA outs and call it a day.

 

Thats the stupidist thing I've heard. Theres a reason WHY there is a ground for your deck. I myself wouldn't use the stock harness ground, but there is a need for the deck to be properly grounded.