Frightfully sorry, old chap. I asked the same question of some well connected friends, about a month ago, and was told "yes" - Chinese inbound tourism had become quite significant.
Hong Kong arrivals had been depressed after the Rizal Park massacre, in August 2010:
http://en.wikipedia.org/wiki/Manila_hostage_crisis
but Mainland arrivals were running at about double those numbers in 2011.
From memory we are looking at around 220,000(?) arrivals in 2011 with 140,000 (?) or so being Mainland arrivals.
This is a significant chunk of the Philippines tourist business - probably more than ten per cent.
Hong Kongers will not give a second thought to what the Mainland wants them to do, but unfortunately the Rizal Park massacre has already done a fine job of putting them off the Philippines.
I will see if I can find the actual figures, and post them.
There is also the PRC's ban on imports of Philippines agricultural produce, which is or roughly the same order of magnitude, but it will be easier to sell those exports elsewhere than to replace missing tourists.
