We`ve had some good rescues here from Epirb activation.
Every 2 years we are required to update and renew registration. AMSA emails a notification when due, you attend to it online, and you go through a number of requirements to renew.It`s the owners responsibility.
If registration is up to date (and there is no reason it should not be) if/when activation occurs AMSA knows what boat,its description,the owner,the emergency contacts,things like that.
Has worked fine for over 11 years for us, fortunately we are not affected by Govt shutdowns. AMSA is if anything, quite proactive in ensuring updating and renewal.