They're not necessarily uploading continuous video of the entire time you're driving to the mothership - that would indeed be wasteful. More likely, they're mon

They're not necessarily uploading continuous video of the entire time you're driving to the mothership - that would indeed be wasteful. More likely, they're monitoring diagnostic values from their autopilot algorithm (like "error in predicted steering angle") and using that to trigger recording of video and sensor values for a short period, which could then be used as "test cases" for future algorithm updates.