There's no fence around the playground at the preschool, so I'm thinking of planting thorny bushes around the border
Maybe not the best choice with the thorns and all. Were you contracted to do such thing?
Not really, I am very concerned about my children's safety.
You shouldn't plan things that are considered dangerous to children. What if someone's get hurt?
That is what I'm planning to prevent with the bushes.
I think you have good intentions here, but need to reconsider the type of plant you've picked out. Pick a bush without thorns, so the children will be contained without the risk of injury.