I'm not so sure she was watching out for you as much as she is a crappy driver.

Sorry for the stereotype ladies of the forum but the car riding my butt WAY to close is almost always a minivan with a female driver.

Some drivers (and it seems to be much more prevalent with women, especially in Minvans and SUV's) I think fixate on the lines on the road. They are incapable of guiding the vehicle down the road without the lines to guide them. When something is between those lines they are stuck there unable to over come without a LOT of anxiety.