Deleted questions lack the "flag" button, preventing us from flagging them for moderator attention. This would be useful if someone feels a question was unjustly deleted, and would like a moderator to look into it.
This is a good idea, but it's kind of tricky because 99% of our queries include the clause
The general rule is that you don't care about deleted posts in the typical case, so we'd have to think that through.
How common is it to need to flag a deleted post, I wonder?
While I agree with quack's comment that it could be useful for users to flag one of their questions that was deleted.
I personally would only delete a question if we don't want it to be visible anymore, else I would simply close it. I can't imagine a case where I would be doing this unjustly.
Deleting should be a last resort solution, so if it has been done that question is likely to be unsalvageable and shouldn't be undeleted.