In response to your cover article "Lords of the Rings” , I make these observations.
If Montecito installs canyon ring nets to catch debris flows, and people do not evacuate because they have ring nets for protection, then those ring nets have created a new threat to public safety.
Ring nets are an engineering solution to a natural event. All engineering solutions have limits — they are built to withstand something, such as a debris flow of a particular size or force. Whatever those limits are, natural events can exceed them. Also, stuff happens. The unusual, the unlucky, the unforeseen, the unforeseeable.