I played with Ingress for a couple of days, using GPS spoofing - but they quickly somehow found a way to catch people doing that (multiple location sources, I'm guessing).
One of the methods of detection is to upload the SSID of WIFI access points around you, including signal strengths. It's pretty easy to spot someone who knows/has pulled apart the client as they usually (accidentally) refer to actions by the internal API method names instead of the UI names. :-)
