Second, since the car already has a Bluetooth radio and interface built in, Tesla would just need to choose (or add) an additional EXISTING Bluetooth Profile (See:
List of Bluetooth profiles - Wikipedia, the free encyclopedia ).. in this case, something like Proximity Profile (PXP) or OBject EXchange (OBEX) or any of the other profiles which may be more appropriate and a profile that the mobile phones already support (possibly one of the more generic ones, like Generic Access Profile (GAP), Generic Attribute Profile (GATT), Generic Object Exchange Profile (GOEP), etc. All it would require is an additional button on the mobile app (if this feature is enabled with a PIN on the car): "Start Model S". When you click it, it asks for a PIN, then the mobile phone contacts the Model S bluetooth stack, the PIN is confirmed or denied, and the car is started.