I think the best course of action is what my folks taught me as a child, try to always e aware of others around you and be courteous. It has generally worked very well for me in 34 years.
You are right though...there is a big difference in someone who is legitimatly trying to get out of the way and get where they need to go and those who just stop out of the blue and pull out a map to have a discussion...We usually have a stroller and I try very hard to keep it out of people's way and have NEVER run into anyone with it...although I have had a stroller run up my ankles several times...and I was still moving...