Hong Kong have been fined $3,000 after fans jeered the Chinese national anthem during an Asia Cup match last month, the third time they have been punished for booing.Fans have taken to booing the anthem as concerns grow that semi-autonomous Hong Kongs freedoms are under threat from Beijing.Despite appeals for restraint and a large police presence, fans booed during the March of the Volunteers, the anthem the city shares with China, at the Asian Cup qualifier against Lebanon in November.