I lease my field out for hay. The guy that cuts it uses an open cutter like that. I also play golf. I don't have the need to go to a driving range when I have 500 yards of field at my back door! You can see where this is headed I'm sure!
After each baling, I can go out and find a whole bunch of golf ball halves!! He cusses me, I laugh back and shrug my shoulders! I know it's wrong, and I actually make every effort to pick up the loose balls. He actually doesn't mind as long as his cows aren't pooping golf balls.
To ease your thoughts, he is in an enclosed cab! AND, he has the curtains! I would definately put the curtains on that thing before somebody gets seriously hurt.