These systems have come a long way since I last looked in on this technology. When I lived in Detroit the Mel Farr autogroup has a system (that I believe was s

These systems have come a long way since I last looked in on this technology. When I lived in Detroit the Mel Farr autogroup has a system (that I believe was semi-proprietary/in-house design) that they would install on high-risk loan vehicles. It was activated over a pager network and would allow them to remotely disable the starter on a vehicle if the weekly (yes, weekly) payment hadn't been made in time. It was not an uncommon occurrence to hear of of see vehicles that were left running 24/7 until the owner could scrape up enough cash for their payment. The system at that time only disables the starter, so once the car was running you were good as long as you didn't shut it off. Obviously the maturity of this system has come a long way since that time (1996ish).