How to child proof a rack

Don't worry I understand, I live in a 2br apartment, and if I had a kid or a spouse, there is no way I'd be able to have a locked reptile room. If I had both, I'd be hard pressed to have as many reptile cages as I do now!

Ralph davis has a similar system on his racks, but it's to stop the snakes forcing the tubs out I think. But his runs vertically only requiring one rod in the middle, which would be less hassel. :D