Key words wave runner "I make it my business to keep myself safe.....   " emphasis on 'My' - self responsibility - hence 70 year olds should be "aloud" to make it their own business to chose to risk their lives, rather than play it safe, and do something they love even if they could die.  I have been mountain running for 40 years.....I am agile and good at it but I am a "senior" who is in better shape than most half my age.   If I die taking a tumble down a mountain trail then I died doing what I chose to do and loving it.  Would rather die that way than sitting in an obese cardiac stupor in the proverbial rocker on the front porch.