Peers can request a channel list from the server at any time, including before a name set.
If multiple apps are using the same server (e.g. you're using a public server), you may want to look into using channel prefixes so the channels the apps use are segregated.
The server can disable channel listing, and non-standard servers can override the option to hide or show a channel given during the channel join event.
The channel listing is usually unsorted, and so ends up in order of first to last created public channel. Servers are free to sort them if they please, but usually don't.