Stupid people.... It amazes the things that are done in the name of privacy. Go look at a database like WiGLE and you will see the same type location info Google is getting about your SSID.
The lat/lon is the location of the war driver and NOT the access point. I just looked at my work address and I found that there are 4 APs that are pinpointed on our building. Not one of them are with in 300 to 400 feet of our property. Three of the 4 have not been seen here in years.
The 2 SSIDs we use are on the map but they are all pinpointed on I-75 and not any where near our building.
If Google is sending data through your open AP which in turn is getting your IP the data is going to be even less accurate because they will get your ISP's address and not yours.