Actually the key `Shift+D` is working as `Alt+D` in meshes because the new duplicated strip is sharing the scene. This task is to create a new `Duplicate Linked` option that will be equals to actual operator and add a new `Duplicate Move` that create a new scene.
New keys:
`Shift+D` Duplicates Strip and creates a new Scene.
`Alt+D` Duplicate Strip but keeps the same Scene.
For other types of Strips is the same the key used because no new data is created (as today).