My children are studying in 國際學校 too. I really cannot image anyone would go from being able to afford 國際學校 to having to 拎綜援.
I think people that used to be able to afford 國際學校, should be able to squeeze out 10K per month to pay the school fees. They has to have some asset they have that worth some money. For example, a Rolex, etc. And this should only last this one month. Because if they really have the heart, they would definitely be able to find a free local school for their children very quickly.
During the times of the financial crisis, a lot of expat families had to leave Hong Kong within a couple of weeks and go back to the US. Those people also pull their children out of international school within a week or so. I think these local families should also be asked to make quick move to pull their children out of international schools and no subsidies should be given to them for international school fees.