In Germany similar to the Uk bonding on the client's side is mandatory as defective electric equipment connected to the gas pipe anywhere in the building could transport dangerous voltage. If ungrounded this cannot be detected properly.
The incoming gas pipe in front of the meter must now have a piece of electrically isolating plastic. This is to prevent 1. corrosion and 2.import of external voltages from the neighboured house for example. Gas pipes other than old water pipes are usually covered with isolating anti corrosion material and so do not have a low ground resistance. (New water or gas pipes now are always in PE outside of a building anyway)
As plastic pipes within a building would be an important fire risk and prohibited, imho it will be impossible to isolate the electrical part of gas equipment from gas transporting part as lamplighter has proposed.
