Surely it is the responsibility of a court would make sure that the parties involved in a lawsuit actually exist?
Civil courts exist to resolve disputes, not to determine facts and sentence offenders.
In this case, the court is presented with a dispute that has been resolved except for the minor detail of deindexing some "defamatory" content---because neither party can perform this action themselves. So the court issues an order to have it done.
While this situation implicitly involves perjury somewhere along the line, the court can still avoid the problem by involving the content host in the proceedings.
In the future, the court could require the host site to be involved in such agreements. This would conceivably lead to the notification of the real author, as the site would presumably contact the user when the suit was filed. In addition, the content can be removed from its original location if it is legitimately illegal.
To do this, the court needs to be technically literate enough to understand where the defamatory statements in question exist. I.e., the Google results will go away if the original host removes them from its site.
Also, the courts must be willing to perform this action for every case of online defamation---it will still be abused in any jurisdiction that does not follow the same procedure.