Moronic idea. Last thing you want to be encouraging in school in segregation of different social strata, stigmatising one group, causing resentment of another, and as someone already said all the kids are essentially getting "free" lunches, the difference is who is paying for it - their parents or the state, but the end result to the individual kid is the same. The pupils are already receiving "free" education anyway, so how is throwing a lunch in having a huge impact on that? Speaking of education, wouldn't kids time at school be better spent learning and studying rather than sweeping floors and wiping tables?
However, I do think entitling some groups to free lunches and not to others to is generally unfair. In my view, lunches should either be made freely available to all pupils, or not at all. Means testing is bull**** and leads to situations where for example you have Family A, where neither parent works, whoa are entitled to free lunches, and Family B where both parents work two full-time minimum wage jobs who aren't entitled, because they're marginally better off economically. The system should reward work and effort rather than penalising it.