Some citizens launched an anti-Extradition Law Amendment Bill movement, namely "Shop with You", in Tuen Mun on November 10, 2019.

Cheng Ting-fung, 19, was charged with participating in an unlawful assembly with other unknown persons at the junction of Tuen Mun Heung Sze Wui Road and Ho Pong Street and failed to produce proof of identity on demand of uniformed police officer Wong Lap-yin.

Cheng appeared at West Kowloon Magistrates' Courts on Monday. Magistrate Jeffrey Sze Cho-yiu said that the witness Wong claimed to have observed the defendant for five minutes, but the video shown in front of the court saw that he was only there for at most three minutes.

Meanwhile, the video could not prove that the defendant had raised his middle finger and shouted slogans at that time.

As the footage failed to prove the defendant's conduct, plus the testimony of the only witness was not accepted and the other two witnesses could not testify beyond a reasonable doubt, the defendant was found not guilty of unlawful assembly.

The defense attorney pleaded that the defendant was only 19 years old at that time and was a student of philosophy at the Chinese University of Hong Kong. He had left his ID card at home but had an Exit-Entry Permit for Travelling to and from Hong Kong and Macau with him.

The judge agreed that the defendant's conduct was due to negligent, but unrelated to what happened at the scene, therefore imposing a fine of HK$400.

The defendant said he could not be too happy whether he lost or won because the damage had already been done.