In Florida and Connecticut, if you are "activated", you are covered. From my understanding "activated" is defined by the SOP for your sponsoring organization. For example, here in CT, we can't "self-deploy". But, it does seem possible that an EM can create rules that say "after a tornado has passed, CERT teams should activate and check in as soon as possible". That way, you can help, you're legally "activated" by SOP. The training keeps pounding into your head "keep yourself safe", so if you actually do get injured, I wonder if you'll be able to recover anything.

Currently from my understanding, only a few places specifically protect disaster volunteers.