This is an extract from the public notice at UBD that I mentioned before when discussing the use of audience to refer to an individual (here).Note the use of shutters to refer (presumably) to photographers. This is similar to the Singapore use of shutterbug to refer to a camera enthusiast, which Adam Brown (Making Sense of Singapore English, p. 114) observes is an American English word that does not occur in British English.
Of course, just like all languages, new varieties of English such as those of Brunei and Singapore regularly create new words and innovative ways of using existing words. Often, this involves borrowing from indigenous languages to reflect local food and customs, so in Brunei English we find titah for a speech by HM the Sultan and nasi katok for the basic dish of rice and fried chicken; and in Singapore we have kiasu, which is a borrowing from Hokkien meaning 'afraid to lose out'.
The difference with shutter and shutterbug is that they are not borrowings, and people who use them are often not aware that speakers from places such as Britain may not understand them.
In the context of the sign, it is probably clear to everyone what shutters means. But Bruneians should be aware of the limitations of using this word in other contexts.
10 hours ago