What a relief!

[Buginator]

That doesn't auto discover all machines running Warzone 2100 on your LAN, does it?
And: Warzone 2100 itself runs code similar to what the lobby-server does (with the exception that it is just for this instance of the game).
To me it looks like your method will only register those games which are run on your very machine, not on any other host in your subnet.

Why wouldn't it see all machines, if you are running the python server code, and they all point to the server?
Using 127.0.0.1 (or actual host LAN IP) for the host, and the clients use the actual LAN IP for the host.

[DevUrandom]

In that case, yes... But that is far from automatic and you still need to know the IP of the host, which makes it just as good as connect-by-ip.