The final cut of the 9th episode of the Tesla Motors Club Podcast, featuring Chad Schwitters, the former president of Plug In America, is now available. You can watch it now on YouTube or listen to it on all major podcast networks.
I the author posting this on another forum. He seems quite genuine but unless it gets a lot of users your chances of passing someone with it are extremely low. And most won't because of battery drain, privacy etc.
Edit: Actually might be different, this app is using bluetooth (tracking cars without the owners permission.. minefield..). I've heard of that kind of tracking being done with TPMS but never as more than a proof of concept.