Suppose you’ve misplaced your Mac. Or someone’s taken it. Or you’re just curious….
With a little craftiness you can use your favourite remote command tool (ARD/SSH… ) to execute a scan for Wi-Fi SSIDs (network names) on the remote host.
thomas$ /usr/local/bin/airport scan SSID BSSID RSSI CHANNEL HT CC SECURITY (auth/unicast/group) HZN507010065 11:2a:de:d9:d9:10 -56 104 Y -- WPA2 H469AEA6914 76:a7:8f:ea:69:42 -79 100 Y -- WPA2
While a list of network names may not directly tell you much, this is where a nifty 3rd party service comes in handy..
http://wigle.net
(free account registration required) allows you to plug in a SSID and it will come back with the locations where that SSID has been reported. I’m not entirely sure how comprehensive their source data is, but in limited testing it is easy to pinpoint a location as long as a few SSIDs are found by the mac.