I'm saying I have check with Botanic Garden, do photographers need to seek permission for shooting weddings and portrait professionally (as in photographers being hired to shoot) inside Botanic Garden?
as for other parks all over Singapore, many wedding couples, family, people have been snapping photos for so many years, nobody rise any issue so far. For commercial shoots, it is necessary to seek permission from the owner of the premises before the shoots.
technical speaking, their is no public space, is either belongs private or our Government,
and FYI, many general public, including security guards, park ranges, classify DLSR as pro gears, so when photographers shooting with reflectors and additional lighting set up as such, whether is real pros or act pro, be prepared to be asked to leave if you didn't seek permission prior the shoot.