Earlier quoted context omitted.
No, it rightfully illicits that response. Wearing a safety device shouldn't make an activity less safe. Your "simple equation" relies on your variables being solid. And they aren't. It's important to stress that the behavioural studies from Bath (that show helmeted riders take more risks in simulations, that cars give them less space) are not data about whether helmeted users are at greater risk. Or that comparisons…
> No, it rightfully illicits that response. Wearing a safety device shouldn't make an activity less safe. American Football vs Rugby and the difference in CTE is often cited as the prime example of where this is true. Helmets and shoulder pads encourage riskier hits.
American Football is all about set plays. You line up and then charge at each other, meaning you have two lines effectively charging at each other and can focus all your effort on this one effort.
Rugby is much more fluid, so the amount of direct head-on-head collisions is much lower, and the distance someone typically runs before tackling someone is much lower as the 'engagements' are more frequent.
American Football is like going from 0-60mph every 10 minutes, whereas rugby is about sitting at 30mph constantly.