I have been to a number of countries to do videography. USA, Japan, Macau, Thailand, Korea, Taiwan, UK, Mongolia, Kazakstan, China, Sri Lanka, Cambodia, Malaysia and of course Singapore. If you talk about Candid shots, as in taking people in the streets walking there is usually no issue. They may even smile and wave at you. If you try to solicit response from them, people are people, so expect shyness. The only no-no responses I got is here when I was shooting a government building a few years ago and the security guard stopped me. He said I needed a clearance letter.