Just having a satellite receiver somewhere in the vehicle passively waiting to receive a shutdown signal, would be nearly pointless because it could easily be found and disabled.
They will have to make it so that you can’t operate the car unless it receives coded satellite signals periodically. The function will have to be integrated into the microprocessor chip in the power train control module (PCM).
Disabling the remote shutdown will entail replacing the PCM. If the practice becomes widespread they will probably legislate against it.
Probably have to insert some sort of system check trick to fool the computers. No signal, no start. After you scan your CONvid QR code of course. LOL!