Earlier quoted context omitted.
...and the more we try to legislate away any possible source of danger we might encounter in our day-to-day lives, the less prepared we will be for places where nature is left to fend for itself.
That doesn't make a lot of sense to me as an argument. "We need to keep life more dangerous in general so that when we hit special cases it'll be easier to deal with" strikes me as generally doing more harm than good because our day to day is going to cause more harm and those special cases are always going to be special. Unless you have specific examples that you're thinking of here.
The "don't put this plastic bag on your mouth" warnings come about because the public supports those laws/cases. Those people are at the point were they rely on other to be responsible for them rather than using common sense. Those laws/cases create an environment where people come to expect warnings for everything rather than rely on their own common sense.
I do think you're right that day to life would cause more harm without any warnings, at least for certain people. The people who are responsible for themselves are generally going to be ok in either situation. The people who are happy-go-lucky and rely on others to think for them and arlt high risk in either situation, sometimes regardless of if warnings are present.