It is legal in Maya to have multiple DAG nodes with the same name so long as they don't have the same parent node.

I know duplicating does this. For example if you:
- create a cube called pCube1
- group it under group1
- open the outliner and pick group1
- Edit->Duplicate

In the outliner you will see group1 and group2. Both nodes will have a child called pCube1.

Off the top of my head, I haven't run into any other tools that re-use names like this.