Your prediction is right on ... that's exactly what's happening this morning. I suppose people are afraid to report such things for fear of being accused of the dastardly deed of "profiling".
I know there are a lot of worried parents and grandparents this morning. And sending the kids to school Monday morning will be very hard to do. Here in Huntsville, there have been rumors (and supposedly substantiated to a degree) of an upcoming shooting being discussed on social media. Over 1000 students stayed home yesterday, and some in days before that. Can't blame them.