Foreign tourists visiting Urumqi, Kashgar and other cities in Xinjiang are warned about fraternising with the locals. And just to make sure they are up to no hanky-panky, there is a check as they exit every location on their tour. The check is to confirm they visited the location including date and time. And just to make doubly sure, the amount of fuel drawn by the driver of their vehicle is recorded to estimate the distance he may have gone. Such is the paranoia of a security state.