I believe they do know, and its far worse than the danger of a broken arm or sprained ankle. It's the danger of being shot dead. I urge everyone to read this article and imagine yourself as a child being told this stuff and "practicing" hiding and being quiet in an active shooter scenario. Far more terrifying than any playground from the past.
https://www.goodhousekeeping.com/life/parenting/a40732/what-...