I personally don't have any issue with a rider traveling behind me running on High beam.
As a rule, TonyK and I ran this method for years. We generally traveled 100m to several hundred meters apart and our light formed a great long steam of illuminated corridor.
I would rather a following rider have the best view forward so 1 I don't feel like I'm robbing them of better visibility and 2 If I go down from roo strike or collision with road rubbish they will have longer to notice and avoid me or my bike or the thing that's caused a failure to proceed.
So, you see it's in my best interest and theirs to leave those lights on high if you're following me.
Others will have a different view.