Currently with feminism all the rage, and sue happy people all the rage, there are lots of good reasons to avoid getting sued.
For example, I know a couple of taxi drivers that refuse to drive women, specially a single woman, because of repeated problems with false rape accusations. (likewise, there are lots of real rape cases with taxi drivers involved).
EDIT: I remembered when my dad worked at a church helping people, and kicked out of his office any women that asked him to lock the door, no matter the reason. Then he explained to me he has a personal rule of never locking himself alone with a woman in a room, unless it is my mom.