from my cage perspective,
dont ride looking around my drivers side if you're gonna have your high beam on because you are completely blinding me.
I got so ****** at this woman on a cbr125 the other day for doing that to me, I wanted to short brake the ***** out of her because of that and the fact that she was rolling through every stop sign nearly passing me as I came to my stops.
edit::
I would say flashing your beams at intersections is a good idea though.
I was driving down rutherford road one night, and I saw what appeared to be one bike approaching along with some cars; I was making a left hand turn. As the car passed and the first (and at this point I thought only) bike entered the intersection I then saw a flash and another bike appeared from out behind the blindspot of the car from my perspective.
It was also a way to let me know that it wasnt a car (two headlights), obviously if it was a car then both lights would have turned to a high beam.
it wasnt a close call or anything, but I was surprised to say the least and it just goes to show that proper "headlight techniques" can be of good use.