I agree that the nagging seatbelt message and noise is irritating (it used to annoy me when backing out of my garage - I didn't put my seat belt on as I had to get out again to close the garage door, but I found a solution - I had a garage door opener fitted)
My only caveat is to make absolutely certain that unplugging those wires won't affect the operation of side airbags (the ones that pop out of the side of the squab).