That could be a lot , the primary was ruled for lots of different reasons
The answer is "this research would not require IRB review because it would be eligible for exemption since the researcher is not interacting with the children and the playground is a public setting".
IBR is a kind of board that applies research morals by looking into the techniques proposed for research to guarantee that they are moral and ethical and do not cross any limits proposed.
There is one word to describe the culture in the Middle Ages and that is barbaric. While some countries were better than others at maintaining order and the education of their society it was quite a rough time to exist when people had little to no rights.