A 100% lawful society is an awful society. A soft prison.
That really depends on the laws. I think most would prefer an overly lawful society over an overly lawless one.
Did they also try plastic and metal? Wood has scent, which I hope they somehow ruled out
I had the same thought and I think you may be onto something. As much as my bias wants me to believe that insects play, there might be something about the color or material of the balls that inspires this behaviour. Perhaps they associate the balls with some kind of pollinator plant and are rolling them in search of pollen. Or some other instinctual behavior is triggered by these balls.
Nature is by and large to be found out of doors, a location where, it cannot be argued, there are never enough comfortable chairs. -- Fran Lebowitz