Since the attack already involves someone with physical access they could hide a transmitter in the same room
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Fast transmissions are limited to a maximum range of 300 cm (10 ft), with the bit error rate being 2-4%. Medium-speed transmissions increase the distance to 450 cm (15 ft) for the same error rate. Finally, slow transmissions with nearly zero error rates can work reliably over distances of up to 7 meters (23 ft).
Since the attack already involves someone with physical access they could hide a transmitter in the same room
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Fast = 1000bps, medium = 500bps, slow = 100bps.