I’m slow on the uptake. I missed this when it came out. (I’m not sure how.) If you’ve ever had orphaned data in your SharePoint databases you want to check out KB918742.
You’ll know you have orphaned data because you can’t restore or delete a site. You are told that you can’t delete the site, but you can’t restore it either — because it already exists or at least part of it does.
Thanks to Chris Chapman for blogging about this.