The main issue is not about debris entering the cockpit (as tragic as the consequences were). That was the freakish consequence.
It is about what happens to parts falling off cars. That was the cause.
Let us not forget that since we are talking about freak accidents, those parts could have ended up in the crowd and killed and injured a number of people. After all, it looks like the stewards realised that, and reacted when they saw Renault not fix the wheel properly (and completely overreacted with a race suspension, but let's not go there...)
So why are we not discussing (let's call it) part retention?
As a former racer myself (20+ years before the bank manager said no more), I am interested to hear from those with an engineering bent on what can be done.
Is it unreasonable or impractical to have more parts tethered, like the hubs are? What parts?
For example, my favorite engineer (who still looks after my road bike for me) used lockwire or a zip tie to hold the spring onto the shock to make sure it stayed as a unit. But he was trained by the Air Force and took a belts-and-braces approach to safety, and the only loose nut in his cars was, well, me.
