I disagree, it is highly relevant. The cause of Dan Wheldon’s death wasn’t lack of a canopy, it was factors that created the accident itself, and these factors are what have rightly been addressed (reduce chance of launching cars, pack racing etc.). The environment should always be safe as a main priority. Had that been the case, an accident would have been entirely avoided in Maria’s case. I’m not saying cockpit protection isn’t an option, but a bizarre accident like that is not a good example, because F1 cars shouldn’t be near trucks in the first place. In the same vein, if Heidfeld had crashed and received head injuries when he drove on the Nordschleife a few years ago, that would be justification for F1 not racing there any more, not evidence that better head protection is needed.
If there is a sudden spate of people drowning in rough seas, or other places/situations where it’s ill-advised to swim, the answer isn’t to make every swimmer in the country always wear armbands, it’s to prevent the dangerous swimming.