It was slightly different for me, had to first be registered on the poors / eternal renters list with the school, after which they'd give you a booklet of paper tabs (like pull-tabs or the old food stamps system), and you presented one of those to the cafeteria cashier after getting your tray of prison-tier carbs, saturated fats, and refined sugars.

Never had anything thrown out in front of my face, but got to sit and watch everyone else eat because I knew I wasn't getting shit without that little paper tab quite a few times.

Dear lord that's fucked, at least where I was at they would make sure you could pay before they gave you the food, that's just extra cruelty, how could anyone think that's the way it should be done? It's almost unbelievable but from what I know of Amerikkka it's not that surprising (if that was in the US).