I am not too stressed out about it. By the time I knew, it was over, and everything was secure. I try to reserve upset for things I can change. There was no reasonable way to expect it might happen, but one of my kids was there (inside a house in the neighborhood) with family members. Somethings you can't prepare for. Somethings you can't control.
I would actually have thought it was more likely at or near my home. My house is a couple of blocks away from a stadium used for school district and some college events. The state fairgrounds are in walking distance, which means big crowds a couple of weeks a year and events year round (including gun shows). I have gone out to deal with groups of unruly teenagers ("get off my lawn.") And I have some expectation of how to respond to an out of control situation here.