this happened to me saturday night in vegas (town square). when i came out of the restaurant we had dinner at, there was a model S sitting in the lane next to the superchargers (not in a parking spot) clearly waiting since all 10 were in use. i saw him and waved him to follow me down to the end (i was at the last one), and moved my car to another spot and he took mine. he got out and thanked me before i went on my way.