When a school district spends millions on weapons detectors, as many have, what is the opportunity cost? While false marketing is a major issue with Evolv (e.g., 1, 2, 3), there is also the issue of what else this money could be spent on. How many teachers or counselors could be hired instead?
A mother with two children at Salt Lake City schools - which recently spent $2 million on Evolv - wrote a letter to the Salt Lake Tribune asking exactly that question. The schools are apparently struggling to manage student behavior: