Yep it is exactly what you think. Some exports have "slipped through the cracks." Many exports have been slipping from Japan to China for months. China will buy and sell anything-especially to Americans.
The vehicles appear to be outwardly sound but were owned by people living close to the Fukushima Dai-Ichi nuclear plant when it was destroyed by the March 11 earthquake and tsunami.
Others come from second-hand dealers in the north-east of Japan, with a report in the Asahi newspaper suggesting that a minivan that was originally registered in the town of Iwaki, on the edge of the 18-mile exclusion zone around the plant, tested positive for 110 microsieverts of radiation per hour. The Japanese government initially set a level of 5 microsieverts as the limit for cars to be exported to other countries, but in August tightened the rules to 0.3 microsieverts