On SP Blogs, users are removing the blog tools web part from the default.aspx page. From what I've seen this isn't in the web part gallery (at least not in our environment). Is it possible to restore the web part without having to export it from another blog and saving it to the site's web part gallery?
Are they deleting it or just closing it? Append ?contents=1 to the URL of your blog and see if it's just closed. If it is closed, then it can be put back on the page. You'll then want to go into the web part options and deselect the Allow Close option.
If it truely was deleted, you'd have to export it from another place and readd it. If you knew the sites where it was missing, you might be able to script something up with PowerShell to add it instead of going through the GUI to do it.