I'm not a fan of the tablet as a pacifier approach but it's not my business. What is my business is when the parents do so without providing a way for the child to indulge without annoying everybody else. I consider that to be absolutely unacceptable in that if they can afford a tablet they can afford cheap headphones.
Yes, only the open-air noise-making kind (per the article topic). Don't care what the rectangle is as long as we can't hear it.