Seems like I've heard the other side say the same thing about movie theaters, restaurants, shopping malls, grocery stores, etc. At the end of the day, I'd rather have the option of using my weapon or not, based on what was happening. And if it's at all like my kid's school then the average kid is 3' tall in that courtyard, lined up with his class and shooting at a 6' tall man who's shooting kids isn't so far fetched.Even if you felt the need, it is unlikely you could use a weapon and then justify it in court given the close contact with those kids. Someone other than the bad guy is going to get dinged.
Do what you are comfortable with, inside the law.