Whistling loudly at police officers, near their ears, is a form of assault because it involves the impact of sound energy, Eastern Court was told on Friday.
Prosecutor Jonathan Man Tak-ho said people should be protected from any form of physical molestation, even when there was no physical contact.
Man was speaking during the trial of construction worker Ki Chun-kei, 50, who has pleaded not guilty to five charges of assaulting five auxiliary police officers – by whistling at them – during the annual July 1 protest march this year.
Man referred to a precedent case in which speaking through a loudhailer into a police officer’s ears was determined to be assault.
Sound can become an unlawful use of force if it is used intentionally or recklessly without the implied consent of victims, he said.
“No matter [whether] it is a loudhailer, a whistle or a human vocal cord, it can emit sound energy, and under some circumstances, [emitting such sounds] constitutes assault,” Man said.
Such whistling is different from normal, everyday whistling, he said.
“He used great force and high frequency [pitch]. He leaned forward and whistled at close range,” Man said.
This was an exception to the concept of implied consent, whereby people commit no crime if they accidently touch others in a crowded place, he said.
The alleged victims – all auxiliary officers – gave evidence on Thursday, saying the whistling was sharp and loud and that Ki had targeted them. All five officers were in uniform during the July march.
Ki said he had not planned to join the protest march. He simply followed the crowd when the road in front of Sogo department store, which he wanted to cross, was closed. He denied being drunk.
Man acknowledged that the charge of assault in this case did not include physical injuries.
But he noted that one police officer said the whistling caused ringing in his ear, leaving him unable to hear clearly for two to three seconds.
Another officer called the sound deafening.
Magistrate Ho Wai-yang adjourned the verdict to January 22, and Ki was released on bail.