[Cialug] _nomap for wireless networks

[Todd Walton]

Google starts a "robots.txt" for wireless networks:
http://googleblog.blogspot.com/2011/11/greater-choice-for-wireless-access.html

Google collects information about a person's location using various
markers, including nearby wireless networks.  Now, the owner of a
wireless network can tell Google not to use his/her access point as a
marker by appending "_nomap" to the network name.

Why would a person want to do that?  What's the benefit?  What's the
drawback of letting someone else determine their location by your
network?

--
Todd