... you're going their way?
In other words, if you're in a group of people and someone's looking for a ride home, how do you feel about someone saying, "Oh, John, you drive right by Teresa's house. How about you bring her home?"
If someone asked you this would you care since you were going right by their house anyway or would you feel put out by someone assuming that it's not a problem for you?
For me, if I offer I'm obviously fine with it, but I don't want someone making that decision for me. Similarly, there was a woman I drove home quite often and would drop her off in Harvard Square to catch the T seeing as she lived on the other side of the city. I found out later that she was annoyed with me for this and felt like I should bring her the whole way home. So I stopped driving her all together.