Why is the Proof of Service Unsigned?

When documents are sent on behalf of a client to the opposing party or the adjudicative body overseeing the dispute, attorneys are sometimes required to complete a proof of service. A proof of service is usually in the form of a declaration signed by an individual indicating that a particular document has been served upon another party.
“Serving” a document on a person means having the document delivered to that person. The general requirements for serving documents are set out in California Code of Civil Procedure, sections 1011–1013a. The proof of service merely serves as proof that those requirements have been complied with. When the served document is then filed in court or with the adjudicating body, the proof of service often accompanies the document to inform the court or adjudicating body that the document had previously been served upon the other party, as required.
So, why is sometimes the proof of service delivered UNSIGNED? Most often, this would occur (in the above example) accompanying the document that was sent to the opposing party or representative.
It would be sent UNSIGNED at the time it is sent to opposing counsel because the declaration itself indicates that the sender “served” or “mailed” or “faxed” or “emailed” opposing counsel. As you can see, I have emboldened and underlined the “ed” in served, mailed, faxed, or emailed. That is because the declaration denotes something that took place in the past.
If you accompany the proof of service declaration with the documents that you are simultaneously serving on opposing counsel SIGNED then you would be – more or less –  perjuring yourself. Why? Because at the time of sending the documents (and accompanying proof of service) you would not have yet served, mailed, faxed, or emailed those documents. It is only after the fact that those documents had been placed into circulation that the underlying proof of service would be ripe to be signed. Because at that time the “service” would have been completed.
So, every court document you send to opposing counsel should have an UNSIGNED proof of service. Nevertheless, 90-95% of the time, attorneys get this wrong.
If you still cannot accept what I am saying because it so challenges your cherished beliefs, here is an official website from a Superior Court backing me up (item 3). Better yet, here is the official proof of service by the Judicial Council, with instructions on how to serve someone, specifically stating in item 3b that the proof of service sent to the other side must be unsigned.
If you still do not believe me, then please check the Code of Civil Procedure that sets forth the rules for service. Section 1013(b) states: “The copy of the notice or other paper served by mail pursuant to this chapter shall bear a notation of the date and place of mailing or be accompanied by an UNSIGNED copy of the affidavit or certificate of mailing.” (capitals and embolden is mine).
So, in the event you ever receive a “CC” of a document sent to opposing counsel from our office, please do not be concerned when you see an accompanying proof of service unsigned. It just means that we actually know what we are doing.