When I was looking at buying a house, I had found something that on paper matched what I sought. So I drove by it to take a look. The place was out in a more rural area. The Confederate flags flown by somewhat nearby homes compelled me to take it off the list.
I had to think about it. Would anyone in the neighborhood attack me? Probably not. Would anyone vandalize my home? Probably not. Would I seriously take the risk of being wrong? Probably not.
This was a long time ago. But something just triggered the thought that a great service might be to mark on realty web sites and/or Google Maps locations who display symbols associated with white supremacists. Like, I can go on a web site and pull up a listing of homes with a sexual offender. This is so people can feel safer by knowing potential predators in the neighborhood. The flag map would identify places that mark themselves as supporting ideologies that might make me wary.
Probably there would be a list of symbols to check/uncheck. Like maybe you think people who fly the Confederate flag outside believe in heritage. So you might exclude them while keeping on the list those who fly the Aryan flag.
Certainly it would not be perfect. People who hold the ideologies but do not fly a symbol would be overlooked. But, maybe people who fly the symbol are perhaps more committed than someone who does not.