Chan and the head of the Small and Medium Restaurant Federation, Gordon Lam, deny breaching a four-person gathering limit at a bar in Mong Kok a year ago.
Kowloon City Court heard that one prosecution witness had lied to the police about her name when she filed a report about the alleged gathering breach.
The witness, Poon Mei-mei, said she “had to protect herself”.
“Seeing someone as sensitive as Ms Chan, it’s only normal to protect yourself, right?” Poon said.
She also said she didn’t realise that police had tried to contact her 15 times in around as many days, explaining that she has two phones and four SIM cards.
The court was told that prosecutors initially wanted to call five witnesses, but there are now only three.
They couldn’t get hold of the other two. Summons were issued, but one was not found and the other later refused to testify.
An arrest warrant has been issued for the witness who refused to go to court.
Poon testified that she was having dessert across the street from the bar and saw how Chan went inside.
The witness said there were around 25 others already inside the premises and she kept watch because she was concerned about “bad elements” at the bar.
The trial is continuing.