I’m in Dayton ohio and it’s common tooCan't speak for other areas, but at least in Cleveland it's common to see the cold, hot, and gas all bonded together right above the water heater.
WAC 296-46B-250 090 Bonding
(8) Hot and cold water plumbing lines are not required to be bonded together if, at the
time of inspection, the inspector can determine the lines are mechanically and electrically joined
by one or more metallic mixing valves.