Upload module doesn't clean out tmp?

I have a client who reports that his /tmp directory overflowed because of unfinished file uploads using the upload module in drupal 5. After some research, I discovered that the (contrib) image module does clean out it's tmp directory via a cron, but upload doesn't. So - I'm not sure if this counts as a bug, or a feature request. I'd think that some drupal core cron that cleans out /tmp might be a good idea, but if not then upload should deal with it's own leftovers, I'd think.