yeah - that happens in my primary school and secondary school too. We often host dinners because we have a school hall, usually the size of 6 badminton courts. Typically the school rents out the hall to recuperate the cost of building it - normal days to badminton players, sometimes to performance groups, dinners like these, even wedding dinners. They might not be "affiliated", but probably they don't charge that much. At least from my experience, child labor is not used for those occasion. The catering, cleaning up etc. is done by hiring outside people, and usually not handled by the school.
But like z says - the principal of the school might be good friends with the minister, and having it at the school allow the guest to come visit the "fortress" that they made.., maybe to get pity donations for the school?
A stadium will be too big - this is not the 20,000 strong rally at bukit jalil in the rain. And it will be odd to put out some round tables in the middle of the field (unless they have an indoor one). Local town hall is usually jammed packed with events. They are (understandably) more expensive and maybe fully booked months if not years in advance.
p/s I don't have an issue with mr. roll eye
-- perhaps we should have a static version that doesn't move
but I still like mr. green best