The "split by the border" problem is pretty common. I looked at a house on Beacon with the driveway in Cambridge. I think the Globe did an article about these places with a special emphasis on school districts. Where the kids actually slept determined what school they could go to.

There are also some houses on Boston Ave in Medford that have Somerville mailing addresses, but they are 100% in Medford. And they have 781 area codes as well.