Warn users of content deleted for copyright reasons

[qubodup]

It'd be nice if sounds/accounts deleted for copyright reasons would state something like

This content has been deleted due to copyright issues. If you downloaded it before, it is advisable to not use and delete this material.

Currently deleting a sound seems to delete everything and probably leaves an emptiness that is indistinguishable from a sound never having existed in the first place. If so, implementing this is probably not trivial.