OK, then I am missing something utterly about how Leaf vs non-Leaf resources work.

Would you code the response to a render_GET in a Leaf resource only?

Or can you do it a non-Leaf resource as well? 

If yes, how do you handle responding in certain scenarios (depending on URL path) in a non-Leaf Resource
vs sending down the request to one of its child Leaf resources?

Jacek