I've read this entire thread twice now.
Yup, I agree with you here.
How do you figure this? It isn't my responsibility to protect the person who lives down the street, or across the street, or next door to me. Where do you draw the line? I think this is really where we are in disagreement. You are assigning to me a responsibility that I've neither agreed to take on nor am required or obligated to take on.
I believe our legal system establishes this at ages 16, 18, and 21 for different actions. Once you hit 21, you're classified as an adult. If you can't accept responsibility for your actions by that point, tough. Learn to deal with it. You're no longer someone else's problem.
Now that depends on the if's and why's and where's, etc. At a ski/snowboard resort, you accept responsibility for your actions by peeling the back off the lift ticket and afixing it to an article of your clothing and then using it. The ski resort has some basic obligations that go along with it, including making sure that the lifts work and are safe. They also take on an obligation as soon as they hire ski patrol. However, you use that facility at your own risk.
There aren't always signs, nor should we rely on them. It is our responsibility to make sure that we don't get in over our heads (so to speak). You have to be in touch with your ability and make sure to take the needed precautions to ensure your own safety. That includes checking out the landing area before using it. It's no one elses responsibility. Regardless of whether the feature is man made or natural.