If you have multiple accessories needing ground on the steering set (bar or fork mounted) you can run grounds to the forward equipment if you install a bonding strap between the main
frame and the steering set. I intend to do this eventually, but have not yet. You can get a decent ground without it, but it is going through the steering head bearings and stem, which is not ideal. A good, low resistance path to ground helps to reduce heat build-up in your connections, just like a good clean power supply does. I'll look around a bit in my manual (bike is not in Maine!!) and see if there is a good point-to point run that can be made and stay concealed. the grounds going to the light housing are depending on the previously described "variable" path. When we steer, go over bumps, and change atmospheric conditions, the quality of that ground path changes, inducing resistance.