In her talk for TED this year Diana Laufenberg says we must let our students learn from their mistakes: to actually fail sometimes and learn from failure.
Her talk is about the importance of experiential learning, empowering student voice and embracing failure. Teachers need to recognise that students aren't actually coming to school to get the knowledge, that is the paradigm of the past. They are coming to communicate and collaborate and put ideas into practice.
It's a great video: just 10 minutes of your time.