If I manually remove a mp3 file I downloaded as a podcast using Rhythmbox, the status of the episode in Rhythmbox still says "Downloaded". If I click on the entry to play it, I get a failure icon, but nothing more. As an aside, this prevents users from downloading the file again if they like.

I guess a simple check for the file's existence would do the trick, and then the file should be downloaded again. It would even be nicer if podcast files were checked for existence at start, so that no 'false downloaded' are shown - though this may bring a performance issue.