I am enjoying reading this. When I was a young teacher I got sucked in a few times by kids who said they had no lunch or hid their lunch. I gave them money. Then I learnt to check lunch boxes/bags.
Now I am even cleverer. When I am teaching full time I have a "fruit bowl" which is my own fruit and if they need extra food they can choose from that then they need to bring a piece of fruit the next day to replace it........I have little printed notes that I pop in their lunch box for their carers/parents. I also have a packet of boring rice crackers. I offer these to hungry kids too.........I rarely have kids in my class want a "free" lunch
I take the fun of "canteen" out and rarely is there a "not enough lunch" problem.
At one school I worked at they made vegemite sambos and offered a piece of fruit for those who had no lunch. This was regularly taken up as was free brekky but only but kids who genuinely had nothing to eat