There is definitely evidence that excessive restriction can backfire and that it pushes youth to take more risks. It takes away positive experiences and positive opportunities and replaces the education, either at the school or at the home level, that young people need.
Again, there's nothing magical about any age. There's no particular point where kids or adults magically become able to manage risks. They have to be given opportunities to make mistakes safely.
Our approach is very much influenced by the approach that's been taken to physical playgrounds over the last decade or so. The approach has changed from making playgrounds as safe as possible to making them as safe as necessary. The approach has changed from removing all possible risks to embracing appropriate risks for children while removing all of the hazards that children either are not ready to deal with or are simply not capable of dealing with because they're not aware of them.