As per more in-depth looking at enclosures in WordPress, 1.3:
I created a new WordPress 1.3 site, and linked an old audio recording of mine (when I tried audio blogging before I decide it was not for me — and if you listen, you’ll hear why) and as you can see in the RSS 2.0 feed the MP3 file linked in the the post has been put into an enclosure. This is not an option in the weblog — you link to a video, MP3 file, or image, it will be put into the RSS 2.0 feed as an enclosure automatically.
This means aggregators can scrape these media files independent of your post.
I would strongly suggest that the WordPress developing team consider running this one past their users.
Since this tends to support some of the assertions that Marius Coomans made recently, I thought he might get a kick out of this post in the test weblog, where I linked directly to a photo of Jonathon Delacour’s.
As you can see in the RSS feed — this became an enclosure in my RSS feed, too.