Two random thoughts: 1. Humans cannot always interact with their surroundings at 100% mental clarity. Stupid mistakes can and will be made even by the most car

Two random thoughts: 1. Humans cannot always interact with their surroundings at 100% mental clarity. Stupid mistakes can and will be made even by the most careful and skilled person. Fool-proof or defensive design features are very well embraced by engineers and the results have been a resounding positive. 2. Some interventions are probably not as benign as people assume, and this could become a confounding factor when it comes to analysing the outcome. Some motorcycle helmets, for example, have been found to trap CO2 at concentrations known to have a negative cognitive effect. https://www.semanticscholar.org/paper/O-2-Concentrations-in-Integral-Motorcycle-Helmets-%3A-Br%C3%BChwiler-Staempfli/6498725e3b95adbd5b99eaee1b131753cfd41b15?p2df https://www.semanticscholar.org/paper/O-2-Concentrations-in-...