It's exactly as legal as it is for me to follow you until you park, and beat the living **** out of your headlights with a maglite.
You asked, don't take it personally. I have a particular hatred for LEDs and people who drive with brights on, since most of my night driving is on very dark country highways. That **** is blinding.
Headlights are getting brighter, and higher, hard to tell sometimes. Anyway I quit flash-reminding drivers whose hi-beams are on long ago, after I did so to a car coming toward me that immediately u-turned, turned his cop lights on, pulled me over, and asked why the hell am I flashing my brights at a cop. Because your hi beams were on, was not an acceptable answer. Also, never pass a cop. Caused as much incredulity. Luckily no tickets for either.
A lot of times small things like a headlight, taillight, brake light, license light, or marker light not shining leads to bigger things like warrants, drugs, alcohol, open container, ect.... I think high beams would fall in to this category.
Driver tried to warn me the other night, but nothing I can do that my normal headlights on my Honda are bright as hell. I probably could light up a whole football field with my high beams.