I've been an elementary music teacher for 25 years. Over the years, I've noticed that children have less and less ability to regulate their emotions: more tantrums, more destructive rage, more crying when challenged.
We used to send disruptive kids to the office. Now when a child goes on a destructive rampage, we evacuate the rest of the class while he/she destroys the classroom. And the rest of the kids generally take it in stride.
I'm in ND. It happens in most schools in my district. Some years are worse than others. One year, we had a 2nd grade student who would send the school into lockdown every day. It doesn't happen on a daily basis in my classroom... I've never had to evacuate my students, but the gym teacher has.