What you fail to understand is whatever "bribe" China can give pales in comparison to the gains of anti chinese talks.I don't think so. More than the US or Japan, China is in a better position to "feed" the Philippines at the moment. Especially that the Chinese don't have qualms of corrupting officials of foreign countries just to get what they want, and the Philippines certainly have its share of easily corruptible officials up to the highest level. But looky it seems that China cannot corrupt its way in the Philippines!
Any corrupt politicians can use the Anti China campaign to strengths their position. As long as they stay in power, the money will come to them.
Not to mention the fact that the policy can change anytime someone new get into power. Betting your foreign policy on that is kinda silly, dont you agree?
One more thing. Like you said yourself. Phillipines have its own share of easily corruptible officials. If they can be bribed by CHina, what is stop them been bought by someone else a few days later? You gonna base your foreign policy on that?