saw this kind of signage at plaza sing too.
nowadays got strict rules, like PDPA
The organiser was prudent in following the PDPA guideline. The example given in the guideline (Para 9.10):
Example: Consent for photo-taking at a private function
Organisation ABC holds a private function for a select group of invited clients and wishes to take photographs of attendees for its internal newsletter with their consent.
If Organisation ABC intends to rely on deemed consent, measures that Organisation ABC may take to better ensure that the attendees are aware of (and accordingly, more likely to be deemed to have consented to) the purpose for which their photographs are collected, used and disclosed, could include:
a) Clearly stating in its invitation to clients that photographs of attendees will be taken at the function for publication in its internal newsletter; or
b) Putting up an obvious notice at the reception or entrance of the function venue to inform attendees that photographs will be taken at the event for publication in its internal newsletter.
Alternatively, if Organisation ABC wishes to obtain actual consent from the guests, an example of a measure that Organisation ABC may take would be to clearly indicate that photographs will be taken at the event for its corporate purposes on the confirmation of attendance form which guests would sign and return to the organisation. In this case, Organisation ABC would be considered to have obtained consent from the guests who signed and returned the form.
For the full PDPA treatment on photography refer to this : ADVISORY GUIDELINES ON THE PDPA FOR PHOTOGRAPHY