I wonder if it would be possible to modify a barrier-spell to allow in anyone carrying a certain sort of object. Theoretically, each child and the supervising adults would be given one - something smaller and easy to carry around, perhaps a coin. Of course, it's not perfect, there's no way, even with magic, to completely prevent something bad from happening, but with responsible adult supervision to help compensate it could work pretty well.
[voice]
I wonder if it would be possible to modify a barrier-spell to allow in anyone carrying a certain sort of object. Theoretically, each child and the supervising adults would be given one - something smaller and easy to carry around, perhaps a coin. Of course, it's not perfect, there's no way, even with magic, to completely prevent something bad from happening, but with responsible adult supervision to help compensate it could work pretty well.