I suspect the probem is not the gps positional accuracy, but rather the data loggers recording frequency - for 99.9% of what you'd want from a gps log on a vehicle, recording the position and speed every 10 or 20 seconds would be more than enough. To generate useful plots of a car driving in circles round a small parking lot would need a much higher recording rate. Even slow old-school gps chipsets output 1Hz position data, but logging all that would needlessly produce 10 or 20 ties more data than youd need for anything except showing up lying journalists. I'd put good money on Musk getting 1Hz or better gps logs of the _next_ bunch of test drivers...