Is it possible to have all octopi operations started by my user to work without passwords? Putting a line into /etc/sudoers doesn't seem to have any effect.

Hm, I removed it and added these two lines to /etc/sudoers:
martux ALL=(ALL) NOPASSWD: /usr/bin/octopi
martux ALL=(ALL) NOPASSWD: /usr/bin/pacman
It's still not working (syncing e.g. still asks p/w), did I miss something?