Since when do sports have to be safe? Having the base coach out there has always been part of the game. The base coach is part of the team and everyone including the fans should be able to see him. The base coach signals in the traditional way, with hand signals that everyone can see. Sometimes the base coach blows it and tells the runner to go when he shouldn't. Other times the base coach makes the right call but the runner ignores him and gets thrown out. The audience can see the coaches signal and see if the coach or the runner made the mistake.

Amateur teams wouldn't spend the money on this kind of equipment, and if the pros do, then it creates another discontinuity between the pros and the amateurs.

I expect part of the fun of being a coach is being seen.