That's really cool! Unfortunately I have ethical issues with systemd, so I'd rather not support it as a first-class option in documentation or out of the box configs. Thankfully something taking over port 79 isn't a concern on any of my threat models for the software. I still require root for low ports on all my systems (to stop takeovers of 80, 443, 22, etc) but something listening on the finger port is going to be pretty harmless. Just don't try to finger hunter2@example.com :p