It has been banned by Ford’s Theatre.
This article is an example of librarians gone wrong. The National Archives reports that one of their historians admitted to using a fountain pen to change the date on a presidential pardon that Lincoln had issued to a military deserter, in order to make it appear to be a significant historical find. Another archivist had thought it looked different than the other documents on display and finally investigated the matter.
Tampering with documents for the sake of fame, in order to appear that you’ve discovered something ground-breaking, is wholly inappropriate and wrong. It is unethical. And it can destroy the historical value of the artifact.
Read the press release and see some more pictures at The National Archives.