I host my own Minecraft server and have online-mode set to false in serer.properties.
Now, I want others to join but I don’t expect them to buy a legitimate copy of Minecraft. Isn’t that why we use this setting online-mode?
In the ol’ days (1.8 and post), I remember using some copy of Minecraft where I could just change my username on every start of this client, and join my server. Period. Done. I want the same again. Is this possible? In a non-illegal way? What about grey-area? I don’t care about security or impersonation (partly).
Maybe not, I think. If third party launchers are legal, and one of these supports offline playing, then it can be used for all online-mode=false servers. But this requires one initial login from a legitimate account. This means you have to give your password to whomever wants to join your server.
Third party launchers that do not check for an official account are certainly not legal. Just do piracy, it’s completely fine.