@petergleick I've never yet found any voice command system in N. America that works with my British accent, so I've given up trying with them.
But at least other cars I've driven had a very clearly labelled button on the steering wheel to activate voice command. The #Tesla? I had to look it up in the manual.
I've driven many many rental cars before, and have never had to read a manual for one. In the last two days, I've had to consult the manual a dozen times, for very basic stuff #UXfail