Videos on YouTube[1] show that the car drives itself even with hands off the wheel. However, I've also read that the car will prompt the driver to keep their hands on the wheel and even turn on emergency flashers/slow to a stop if the driver failed to do so [2]
[1] https://www.youtube.com/watch?v=Cw7Esg-txR0 [2] http://www.wired.com/2015/10/tesla-self-driving-over-air-upd...