Local students are often criticised for being apathetic about politics and ignorant of current affairs. The students who disrupted the Chinese University's annual graduation ceremony on Thursday could never be accused of that. Sadly, though, the 20 or so protesters let their enthusiasm get the better of their judgment. In short, they went too far.

Young people should be encouraged to take an interest in politics and to openly express their views. Free speech underpins our open and vibrant civil society. Protests, by their nature, tend not to be polite or gentle affairs. But there are many ways of getting a message across. There are also appropriate standards of behaviour for different public occasions. Some of the students at the ceremony crossed the line. The target of their protest was former chief executive Tung Chee-hwa who was receiving an honorary law doctorate. The protesters did not think he deserved the degree and were entitled to express that opinion. But the students should have remembered that the occasion was not held in Mr Tung's honour alone. It was also important for thousands of fresh graduates and their families celebrating their achievements. The graduates had worked hard. Many of their parents had made enormous personal and financial sacrifices to achieve a better future for their children.

The whole ceremony lasted slightly more than an hour. But as soon as it started with the national anthem, protesters tried to rush to the stage, wrestled with security guards and shouted down anyone who tried to stop them. This lasted on and off for half of the ceremony. The students, in effect, hijacked the occasion. Also, one does not need to be patriotic to know that the anthem of a nation represents its people, not necessarily their government. It deserves a show of respect. A group of 80 elderly protesters adopted a far more decorous approach. They waited outside until the ceremony was over before chanting slogans to demand increased welfare subsidies. One even confronted Mr Tung outside the venue but inconvenienced no one except Mr Tung. It is good to see students taking an interest in public affairs. But those responsible for the unseemly scenes at the ceremony should re-examine their actions.