High Beams on Urban Bike Trails

I regularly bike on a paved trail in my city that runs along a boulevard and even has light poles, but when I'm riding in the evenings I'm constantly blinded by other cyclists' high powered headlights, especially ones worn on the helmet pointing directly at eye level!

I literally can't see the ground without shielding my eyes and looking straight down as far as 100ft away. When they get into shouting distance I try and yell as calmly as possible "high-beam!", but most times it goes completely ignored.

I'll pass at least half a dozen riders like this on a 2 mile stretch, it blows my mind.

Does anybody else noticed the same thing in their area? It really steams me up because I see it more often now there are more riders, I want more people biking, but the use of high powered beams like that drives me nuts.