Sunday at the Basketball court

we were at the basketball court Sunday night had a great time and some awesome food form the vendors there but have a question as to the empty chairs with picture on them, my Spanish is limited so reading the banners I was only getting a word or two' but thought it was missing person's ?

I'm going to take a wild gues and say it was a demonstration for the "missing" students of the Ayotzinapa teacher's school..