[Tails-dev] method to verify a running live sytem

Hi
I live in an occupied area where we use Tails a lot.
I wonder if there is a method to verify a running live sytem?
The case is:
How to verify an USB key to be sure the installation is safe (=conform)
in an unfriendly context?

Another think:
It should be great to have checksums in the offline documentation to
verify ISO without Internet connection ;)

Thanks for our job!