Where is this (generally, obviously), that your kid has the choice of meat substitute any time there's a meat main? Both my kids are vegetarian and of there's a meat main, they are getting sunbutter sandwiches.
This is in MA, though, where we have universal school lunches.
I assume your school has a cafeteria then? Not the case for my school. It seems to be a struggle to get even one hot lunch going. At this point, we might not have anything set up until mid November.