Section 9 of the POBO states that an employee of a private company cannot solicit or accept any advantage in relation to his employer’s business without the permission of his employer.
"Lai see" is a kind of advantage. The cleaning worker must obtain permission from his employer (the owners’ corporation or property management company) before accepting any advantage relating to his official duties.
An employee of a private sector company must obtain permission from his employer for accepting any gift offered by the customer, supplier, etc. Custom is not a reasonable excuse for accepting an advantage.
Text of Prevention of Bribery Ordinance