no eating on the bus

I've been asking the school to enforces its "no eating on the bus" policy for the upcoming field trip. The school is protesting.

Lets see, let's take 50 kids with peanut butter and other nut products and put them on a bus for 4 hours. Let's have them all eat on the bus. Then let's put a nut allergic child on that same bus and see what happens.

The liability and legal ramifications to a school who knowingly puts a child at risk, when something as simple as a "no eating on the bus" policy could be enforced, seems like a huge set of dice to roll.