It's been a problem for a looooooong time, the only thing that I really didn't like about Flickr, and it made me uncomfortable if I ever thought about it for too long: Up until very recently if your Flickr account was deleted that was it, it was gone for good. Whether it was an accidental deletion on your or Flickr's part, malicious due to hacking, etc, or whether you'd violated Flickr guidelines - it didn't matter how or why it was deleted, it was just gone.
Now I'm not worried about losing the photos themselves (I have them offline), but comments, tags, titles, descriptions, and other metadata represent a significant amount of time and effort and this is before you even get to where else you might have references to the photo urls (blog posts, etc that will have to be fixed). And although I try to get most of my metadata in order offline, before I upload, the convenience of being able to add/edit titles, descriptions, tags and location data from any computer is too great not to use (Ideally a tool that not only uploads, but syncs with Flickr would be best, but it doesn't seem to work in practice). That reminds me, I really should finish my post about the Cloud, but the basic premise is that convenience always wins, but it shouldn't have to come at the complete cost of data integrity.