Signal from the key just needed to start, not a keep-alive. Might depend on make/model. Chances are good an automaker doesn't want to shut off a car at speed just because the key misses a keep-alive ping.
The device is actually two sets of equipment. When the unsuspecting victim parks and locks the car, a thief standing not far away holds the first device, which is used to pick up and amplify the electronic signal as it is sent between the car and the key fob.
That signal is relayed to a second device, which tricks the car into thinking that the key fob is near the car. That disarms the security system, unlocks the door and authenticates the engine to start.
The device is actually two sets of equipment. When the unsuspecting victim parks and locks the car, a thief standing not far away holds the first device, which is used to pick up and amplify the electronic signal as it is sent between the car and the key fob.
That signal is relayed to a second device, which tricks the car into thinking that the key fob is near the car. That disarms the security system, unlocks the door and authenticates the engine to start.
https://www.latimes.com/business/la-fi-hy-mystery-car-steali...