2 sets of eyes when performing patrols is good practice. 2 sets of eyes crashing to the ground when performing vertical reference work is just plain stupid unless you are flying some old equipment that needs an extra 200 lbs to function properly.
ie - SCE used to use 2 pilots in their 135 when the AFM requires one. They should have learned to longline from the right seat.
429 is likely a better fit for them.