I guess they can do what they want, but I would be annoyed. Even though we eat that way 90% of the time its a bit patronizing.
The burrito example that someone posted is great. Healthy eating encompasses a whole range of eating options - we spent 3.5 years in Japan where white rice is the norm, but is in small portions paired with veggies and fish. Is it as ideal as brown rice? No, but seems waaaay better than the allowed fish sticks and chips and juce mentioned in the article. And yeah, are they actually checking people's peanut butter snadwiches to make sure its no-sugar added instead of Skippy. Also, not everyone agrees and what is healthy. I don't like to give my son raisins because they stick to the teeth really bad and can cause dental problems. I also guess my homemade whole-wheat pumpkin muffins would be out because they have sugar, even though its only 1/4 cup for a whole huge batch.

I think ideally there should be some food guidelines and a no-trading rule, but actually policing lunchboxes and throwing away food seems a sure way to make kids neurotic about food.