User can upload videos and create playlists with that videos. What would happen if the user deleted videos used in a playlist? Should a playlist be also deleted?
Additionally to @Dipak's answer.
Lets say a user has a playlist with 3 elements. The user deletes element 1. After he deletes element 2. When he deletes element 3, he might not realize the playlist will end up "empty". So when the user deletes the last element you could:
- inform him that the list will be empty
- ask if he also wants to delete the list
Otherwise the user will wonder why the list isn't showing where it should. An empty list might need to have a different display than a filled one.
I also believe that it shouldn't delete the playlist.
Making the analogy of a playlist as a "folder": the same situation if you create a folder on Gmail and it doesn't have any email inside; the folder continues to exist. The same if you have a folder on your OS and took all the files from it. The folder is still there.