Have you seen the locations? These are for intra-state transit. Not for getting home from work. The locations are really only for making long trips feasible you would otherwise need to rent a "real-car" to take. Like SF to LA or what not (or tahoe, or La to vegas). In that context, it both seems less likely to find a backup at a station (because few tesla owners would not just Fly, be realistic), but a bit more of a hassle (extra 1 hr on a 5 hr drive, etc). You'd also expect to see "full" charges, because of the destinations.
TL;DR Its not the local/commuter crowd they are catering too.
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Edit: Locations - Only the LA and Fremont are even somewhat near major metros.
SF/SValley to Tahoe = 1x (Fremont)
SF LA corridor = 3x+1 (harris ranch, tejon ranch, gilroy, LA)
LA to Vegas Corridor = 1x (barstow)
SF-Tahoe-via Fremont seems the most likely actual drive for the target audience. Its only 1 of 6 locations.