“Brunei’s interests in the South China Sea are primarily economic,” says Jonathan Spangler, director of the South China Sea Think Tank in Taipei. “It depends economically on resource extraction within its claimed exclusive economic zone, and at the same time maintains close economic ties with China. Although China’s nine-dash line claims overlap with Brunei’s EEZ claims, both governments understand that avoiding diplomatic or military confrontation over the issue is in their best interests.”

https://www.forbes.com/sites/ralphjennings/2017/03/06/why-brunei-will-always-be-nice-to-china-in-their-sticky-maritime-dispute/#4a6cf1fc211a