Sure, he has a right to be there, he's the owner.
But why is he there? What purpose does it serve? In what way could he contribute to a better practice? Lol, is he trying to "inspire" them?
How much time and attention will coaches and players have to dedicate to him being there when they could be doing something more productive? What type of message does it send to players when it comes to having confidence in his coaches? He might very well have zero confidence but you don't display that.