I think Russ's point is that you can provide detailed information on the NOAA registration page concerning your current trip in the comments section. Thus, if you activate, the SAR guys will have access to that information. I do not have my PLB ID handy at the moment, so I cannot get in to confirm this. He's not talking about the ability to compose specialized messages on the fly, but thinking ahead to add information to the NOAA registration page before you leave.