In an app I work with, the users can modify the category a document belongs to from the document-editing interface. When the category is saved, all documents that belong to the category are updated with new paths.
Sometimes, when a user saved the document after modifying the category, a save-conflict would occur (I couldn't recreate the save conflict in Firefox for some reason, only IE).
Simple code to remove the field:
var f = document.forms;
f.removeChild( f['%%ModDate'] );