> What you actually need to do to defeat this is a bit more expensive. You need the token (keyfob, card, etcetera) to be smart enough to use the tiny surge of power to do local computation, and then produce one-time-only access codes.

Why do you need the keyfob to rely on a "surge of power"? Can't you put a battery in it and charge that battery when driving? If the battery runs down, you needed a backup anyway (physical key or phone app) in every implementation I've seen.