These new systems suck because there is never free time left on a spot when you find one. They automatically reset when the last car pulls away, increasing overall parking costs for consumers.
Sorry, in this case you are mistaken - the sensors in San Francisco will not be used for meter-zeroing. In fact, they can't be used for meter-zeroing - while they are fairly accurate, they are not accurate enough for this feature. Imagine if the meter was zeroed before you'd actually left!