What's not being acknowledged is the effect on the children. Imagine the humiliation suffered by the children when the get to the end of the line, only to have their lunch taken away from them in front of the other children, then thrown away. Put yourself in the shoes of one of these children! These are elementary school students, not adults, or even high school students! A policy that causes a child to suffer that is appalling!
The School Lunch Program wasn't established to provide a convenience for parents, or a source of revenue for the schools. I'm sure school districts could think of much better ways to utilize space and staff. It was established, to provide, in some cases, the only decent meal a child may have during the day.
So, yes, the school district deserves to recoup these expenses. Yes, parents, like myself, are responsible for taking care of these obligations. But, do not take this out on the children!