I think people know that if they go to watch high speed sports there is an element of risk involved. Same thing happened at Le Mans many years ago when an engine cut its way through the grandstand after an accident.
Bad news, but would I go to Reno....? You bet I would and if I weren't working this year, I would probably have gone.
Fate is the hunter
Official death toll for the '55 Le Mans is 83 spectators and the driver (sadly there was a lot more flying into the crowd than 'just' the engine). It certainly was a big shock even back in the days when safety wasn't really that high on the agenda (BTW to this day, motorsports is illegal in Switzerland as a result).
Looking at the car racing scene shows that progress in safety can be made. The following chart shows the average yearly death toll in F1 racing. F1 has come from times where it was perfectly normal to bury 1 in 10 drivers per year (not even counting those getting killed off track or while driving in different series) to not having lost a driver for 17 years now (knock on wood).
Yes, motorsports is dangerous (as is flying). That doesn't mean you shouldn't take a hard look at the risks involved and minimize them where appropriate.