This application will run on iPhones or Blackberries. With the Sensory Internet (see previous entry), it will know what we are up to, and what we are currently doing. Using Bayesian inference, it will determine the risk of our activity and notify us if the risk is large. It will keep us on our toes.
Something simple like this will save lives and prevent stupidity. The only annoying thing will be the beeping when a married man is talking to an attractive woman.