Not needed on a bush walk

I found this discarded crushed tennis ball on our bushwalk this afternoon (now in our bin) and I found myself wondering why?

Why in a place so rich with natural stimulation for your dog would you feel the need to throw a ball, (especially one that grinds down a dog's teeth like sandpaper)? With your dog focusing on the ball, it's missing out on all the other wonderful things in the surrounding environment.

And please, let's all take better care of the environment