Let's say you're a minority - we'll go with race, since it's visible and in the news these days.
You're with a small group of friends who belong to this group. At a lunch in a food court, you notice one friend heading toward a place known for tasty food, but also known for its support of abhorrent policies and politics. Let's say it's "Circle Triple K." This is a place where you would not spend money in a million years, because you have some political awareness and have spent time developing a sense of money activism.
Do you advise your friend of the situation then and there, stay silent, or choose another course of action (such as blogging about it anonymously a few days later)?