There's a difference between not knowing and knowing but still choosing to do the activity.
I ride a motorcycle, and I am fully aware of the dangers involved. I also know that going the speed limit, wearing a helmet, and not drinking anything will significantly reduce my risk of death, but that it's still more dangerous than driving a car.
At the same time, I know that breathing in sawdust, paint fumes, and many other things is dangerous for me, so I have a mask that I wear when doing work around my house, and I ensure that there is good ventilation. The "cost" of doing those things is small compared to the possible benefits, so I do them. And without the information that those things are dangerous, I would be putting my wellbeing at risk for no good reason.
Which begs the philosophical question, if we continue on the trend of trying to reduce risk and take that to its extreme conclusion, what is really left of life? People do tons of things every day that put them at risk of an early death --- many of them even enjoy it.