This has also become a problem as a cyclist. I live in a bicycles-first city, commute that way almost every day, and over the past decade when LED lights became the norm, almost every day during this time of the year there's at least one person that just mindlessly snapped their headlight onto the handlebar. It might just fully shine into your face. Back in the days of those dim incandescent bulbs powered by whimsy generators, it basically didn't matter which direction the light pointed, but with super efficient battery-powered lights, this is annoying. And if both of you are traveling at even just moderate speeds, you don't even have time to communicate the issue in a proper way, except for maybe shouting "it's blinding" and hoping the other person can put two and two together.