Is a person who eats halal vegetarian food in restaurants that serve alcohol or pork, sinful, knowing that his food does not mix with the forbidden?

A Muslim woman should not sit in restaurants where alcohol and pork are served, even if her food is permissible (halal), because such an environment is not free from witnessing forbidden acts. This prohibition is even more emphasized for women due to the fear of them being exposed to harm from alcohol drinkers. A woman can buy food and eat it elsewhere.