Yes. Number one, even halfway intelligent people know that the third base LINE is where you are going to encounter screaming line drives. Why would a grossly negligent parent place a child there unless they are willing to fend off foul balls? If I had a child THERE I would have me glove handy. Jeez, YOU CANT FIX STUPID.
Not everyone that goes to a game is as knowledgeable about baseball as perhaps you or I. It may not be a matter of intelligence, but knowledge. Being a baseball fan and having kids, I don’t buy field level tickets down the 1st and 3rd base lines for the reason you mentioned. I would like to be able to look down to grab another nacho or perhaps even blink at some point during the game without having to worry about someone in my family getting smoked by a line drive.
In this litigation-happy society we live in, teams are going to realize that providing some reasonable protection down the lines is a heck of a lot cheaper than the alternative. How many personal injury lawyers do you think have seen that clip and offered their services already?