It does indeed, I use it all the time. Very useful functionality.
What I was rather poorly referring to was calling the Rhino.RhinoDoc.AddRhinoObject event from a GHPython component. I just tried it out quickly yesterday using your code and had no luck getting it working (works from the editPythonScript editor though). I have very little experience with events, but would like to get started. In this case I was looking to write a GHPython component which reads geometry from nested Rhino layers and have this component automatically update if new geometry is added to the Rhino doc.
I’m afraid I’m not currently on a Rhino machine, so I do not have any definitions to upload available.