However, if an image is on commons and a project doesn't want it there is no way for the project to stop the image from being used.. other than abusing the badimagelist or tracking down each and every time someone puts it in an article. They lose the ability to make a decision once and have it bind.
users can just reupload it under new names if they want to war over an images use anyway.
there are plenty of mechanisms already in place to deal with users who are disruptive or edit war.