Its annoying, but its not a problem. Put a hand up. Block the direct beam into your eyes. Use his light to see the path. He'll pass by in a few seconds. I usually aim my MagicShine to put the meat of the beam 20' out from the bike. Everytime I hit a bump it shifts and always upward. Even if I don't hit any major bumps after 5 or 10 minutes the light shifts upward. There is a position which seems to make my light happy and where bumps or time do not change the orientation of the lens. The beam just grazes the surface of the road and if something is down the road that needs lighting up it gets it. This would appear to be the most efficient position of the light. But not the most neighborly. I am sure that an oncoming cyclist on an MUP is going to be momentarily blinded by the light in that position. I don't ride MUP's but I ride at night enough to know that by the time you see the oncoming cyclist and manually dip your light you would already be past him or her. Unless they also have a light that you can see a long way off. Some riders are going to try and dip... some are not. Kind of like drivers and high beams... ...

H