Looks like civilian GPS accuracy is 4m or so. I could imagine that dropping someone's dot in the middle of a street, and then a driving having to guess which side of the street the error is coming from.
Some places will put both evens and odds on the same side of the street if there's only one side, and then use more numbers if there is subsequently development on the other side of the street. Some places will assign a new house number whenever a new building is added, no matter where it is located. Some places will number in clockwise (or counterclockwise) direction.
