It's been exactly six months, and I've yet to see a single wireless access point with a _nomap suffix. This must be good news for Google. After all, if nobody opts out of something they don't know about, then the status quo is maintained. Sounds like a great solution1 that provides "greater choice" for people who don't want their networks mapped to a GPS location.
On a side note, I wonder how many people remembered this little blip in the news from last year. It caused quite a stir in the tech circles, but that's about it. Since then Google's been in the news for a dozen other things, both good and bad.