CCP 415.21 has been revised as a result of AB 2256 (Garcia -2014), and effective January 1, 2015 requires only that a Registered Process Server prove their identity with an official form of ID (e.g. Driver’s License) and a current Process Server Registration. The code no longer requires an RPS to identify the Party to be served. Guards had often required the address as well, but the code did not, and does not require that the address be provided. Here is a link to the code:
You may wish to keep a printed copy in a plastic sheet protector in your car to show guards if need be.