From the article
> Basically, a phone unlocks the car using a combination of cell service and Bluetooth. So when you're out of cell range it can be difficult to unlock the car.
> They were unable to ping the car because, I don't know, they hadn't updated, or synced, the software in 24 hours.
My understanding is that it works like scooter and bike sharing services, where you have to have an active connection to their servers to use the vehicle. Of course, while it works in the city where there is 3G/4G coverage, it's not going to be efficient in the middle of nowhere where coverage is unlikely... so sometimes convenience (AKA it's just an app) becomes a hindrance. Who's fault is it? (rhetorical question)