Say there is a multiplayer game (or radio station, BitTorrent tracker, etc) that would (at least threaten to) ban users if they are using a modified client. And the official client is released using GPL. Does it work?
Intuitively it isn't that free as the GPL intended. But some problems are:
- The software could be released by a 3rd party, who doesn't seem to be able to forbid the service from using it as the official client.
- It doesn't disallow you from running the software. It just disallows you from connecting to the service.
Yet in the game case, the software might have no useful functionalities if it couldn't connect to the service.