MS CE 14
In the Level Manager dialog menu Levels-- Import... does not check if a level is duplicated.
Example:
Mi current drawing has the level "MyLevel" with color Red
If I Import a DGN file which has a level "MyLevel" with color blue, if I select that level in the Imports Windows, that level overrides my level.
When we do this with a style in Civil 3D, it always shows a dialog with several radiobuttons:
Overwrite.
Ommit
Create copy (with a suffix "-copy") or change name
The attached file is a window in Civil 3D when you try to import a duplicated style from another drawing