> it's described in point 6 here:  
> http://doc.akka.io/docs/akka/snapshot/general/supervision.html
> but that doesn't match what is written here

I believe you! The comment I followed was:

"I prefer the constructor for non-childish things, but for creating and  
starting children, I prefer preStart().  The reason is because I can  
opt-out of child-stoppage in preRestart(), and if I've created children in  
the constructor, then I have no recourse to ensure that duplicates don't  
get started.  This just provides me with a pattern that "generally works"  
and is resilient to refactorings a bit more than the other method."

I think I will close this PR for now, and wait until I can discuss it with  
Roland.