Here's the setting in VLC I'm looking for: "disable all network activity?" [check yes], done. VLC is now permanently in "offline mode." Does this simple setting exist?
Don't really care if the setting disallows incoming connections as well. I'm a recent convert coming from win7 and really missing the application-based firewall which worked so well. gufw is like a fisher-price firewall compared to the windows firewall and custom ipsec rules you could setup with the MS snap-in console. The "accepted solution" appears to be extremely inconvenient, especially when the "arguments" to VLC will be whatever media file is double-clicked.
The other possible solution is an experiential firewall that you need to compile yourself. I don't understand the words: "Quick start: Run lpfw as root. Run python gui/gui.py as regular user." I'm assuming that translates to: "sudo lpfw" and then I don't know what the python bit is.
I noticed in /usr/bin, vlc and vlc-wrapper permissions can be set to a different group. Following the above instructions again, can you simply select group "ni" here for both items and then you're done permanently? They're currently on group "root".