If you agree that bonding can reduce the risk of arcing then you should consider this. Relying on the underground copper gas line as a method of bonding is a flawed idea. Point being, what is it bonded to? The earth? That's grounding not bonding. Bonding ties systems together, usually at the main electrical panel. For the risk of arcing to be reduced to the lowest potential, all systems need to be tied (bonded) at a point which is then run to the grounding method. If the pipes are grounded at one end of the house and the wires at the other, there could be a difference in resistance in the two systems. This difference in resistance encourages arcing. It's best to bond everything together then run to the same grounding method. Two different grounding methods invites problems.