Channel names on QuakeNet are case-insensitive, and you do not have any real control over how the characters of your channelnames are capatalized. The explanation can be a bit tricky, but there will be examples in the end, to clear any misunderstandings out.
QuakeNet consists of around 38 different servers combined in one network. These servers share channels between them so you will be able to chat with the people who connected to any of the other 37 servers. When you are the first from a server to join a channel it will be created the way you specify it when joining on your particular server, even if the channel already exists with users who are connected to other servers. If someone who are connected to the same server as you are had already joined the channel, it will be displayed as they wrote it and not you.

Note that if all the users from a particular server leaves a channel, it will nolonger exist on that server, and the next user (connected to that server) who joins it, will create it yet again with the uppercase and lowercase letters he/she specify. Even if the channel has previously been saved with a different name.

Burt who is connected to dk.quakenet.org wants to create a channel and finds #moocow was completely empty (apart from him). He ask his friend, Carl, who is connected to se.quakenet.org, to join the channel #MooCow - as he does. In Carl's IRC client the channel name will now look like '#MooCow', while it in Burt's client will look like '#moocow'. Burt now asks another friend, Peter, who is connected to dk.quakenet.org like him, to join #MOOCOW - In Peter's client the channel will be displayed as '#moocow' because the server had already created and saved the channel with that name when Burt initially joined it.