“For an action like designating the Scarborough Shoal as a marine sanctuary to have a deescalating effect on South China Sea tensions, it would need to have at least tacit approval from relevant claimants,” says Jonathan Spangler, director of the South China Sea Think Tank in Taipei. “Otherwise, it risks leading to escalation, regardless of whether Manila’s intentions are related to environmental conservation or not.”

http://www.forbes.com/sites/ralphjennings/2016/12/07/new-maritime-move-by-manila-will-strain-china-philippine-relations-again/

From interview transcript:

“For an action like designating the Scarborough Shoal as a marine sanctuary to have a de-escalating effect on South China Sea tensions, it would need to have at least tacit approval from relevant claimants. Otherwise, it risks leading to escalation, regardless of whether Manila’s intentions are related to environmental conservation or not.”