Weird idea for placing ant bait around daycare, need thoughts

I work at a college campus, and we have a daycare on-site that has pretty bad ant problems. It's difficult for our pest control company to spray, because the kids play outside, and we can't place bait traps around because the kids will definitely drink them and die. Our pest control is doing the best they can but they always come back and the daycare staff freak out because they're required to shut down if there are pests of any kind.

My idea is to build small locking boxes that can be attached to the wall along the floor at various points around the building. They'll have holes cut along the bottom to allow ants in and out. We would open them with a key, and place bait stations inside. The box is secured to the wall so the kids can't pick it up, they can't open it, they can't get their fingers inside it. And then we just have recurring maintenance order to go in and replace them when the bait expires.

Is there a better way to do this/commercially available products that already do this? Or does anyone have a better idea?

Just for context, I'm in the PNW, the building is entirely ground floor with a slab and no sub floor. The ants we're getting appear to be little sugar ants.