I don't administrate an offline Trisquel, what I want is an updated Live USB
that:
1) has the latest security updates installed before going online.
2) has software packages added that aren't bundled with the default ISO.
I want those things so that:
a) I can install on multiple machines, knowing they are running identical
software, without having to download multiple times.
b) I have a Live USB distro that effectively demonstrates Free Software.
The offline install route seemed simpler than the ISO update method. The
signature file side of apt-offline adds complexity which is only necessary
when working with different base installs, which isn't the case here.