I don't follow a person's name, I use focus. But I know that many vehicles clear my focus when I get in them. I just push my /focus LeaderName macro and it works no matter where or what people are. Then I just use my /follow focus key and it makes the vehicles follow. Maybe you can't /follow names since it gets pissed that the person is in a vehicle. Just have to learn to adapt a macro to stuff that works.