We do on a regular basis, it's just that most of the accidents are relatively small-scale, like one person being mistaken for an explosive-vest wearing terrorist chased onto a subway train and shot, or just one of many reactors being made to go Chernobyl, or just the occasional huge dam here and there failing and damaging a few million homes: https://en.wikipedia.org/wiki/1975_Banqiao_Dam_failure
Most people aren't sadistically malicious, and most security is professional, so random little failures like metalled balloons or reflections off clouds (or the moon) scaring a security system will only blow up to something important (even on the scale of previous paragraph) every decade or so.
