Legal Question in Civil Litigation in California

To serve a lawsuit upon a party, mailing the suit is insufficient. The letter might be to tell you that you wil be sued but it does not do away with them having to attempt to serve you personally. Failure to pick it up means you do not see the contents and the sender might try to serve you at home or at work. The other side might be able to get some of their costs of service back.

Service of a summons and complaint by certified mail is not an acceptable form of service in California, in and of itself. A party may service a copy of the summons and complaint, along with a notice of acknowledgement of service, but service would not be complete unless you signed the acknowledgement of service and mailed it back. Substituted service also contains a component of mailing, but only after a process server left documents at your address with someone over the age of 18.

Some important notices are sent via certified mail, such as IRS notices, and notices of pendency of action. Why don't you sign for it and find out what it is, rather than hide from it and be forced to dig yourself out of a hole later?