Our school allowed a single treat on Monday, but in general, no treats in lunches.
As a parent who is pretty liberal with treats in general, I have no problem with a policy that helps children eat in a healthier manner. My kid can survive just fine without a treat at lunch - she can have it right after school, or before school, or after dinner, or any other time.
Not all kids have treats in their lunch, and it’s hard for educators to monitor who has a treat and to make sure they eat it at an appropriate time. They also need checking to make sure they are school safe.
Our teacher believes very strongly on healthy diet =healthy minds, and I support that. I don’t even send in cookies, but that’s a personal choice. There’s a jillion other hours a week to offer treats.