When player enters the singleplayer mode, there's no option to disconnect from it. Player either can quit to desktop or create a new singleplayer game. Only way to disconnect from singleplayer without quitting the game is typing "disconnect" to the console.
This may be confusing for new players.
Disconnect option can be easily added editing this string on GameMenu.res
{
"label" "#GameUI_GameMenu_Disconnect"
"command" "Disconnect"
"OnlyInGame" "1"
"notsingle" "0"
}

For SP I'd rename it to something else as disconnect fits MP servers better..
For SP I'd rename it to something else as disconnect fits MP servers better..
It's a little bit hassle to do that. You need to add new row to menu and sort menu for the new row. I'd say save the hassle and go with disconnect.
What's the reason to have a disconnect option from single player? Add Find/Create Server options to immediately go online instead if possible.
What's the reason to have a disconnect option from single player? Add Find/Create Server options to immediately go online instead if possible.
Simplistic and consistency with other titles. Like in CZ:DS

That simplistic and consistency approach seems quite wrong. Because a disconnect option will just take you back into the main menu, while you have all it's options in single player. The only real reason to go back into the main menu right now is to go online if I understand this correctly.
The method you're suggesting may break the mods. Not every mod has custom GameMenu.res and most of them doesn't even have Multiplayer. It'll be odd to see LAN options on a singleplayer mod. Infact i don't see a reason to stress about this issue any further because literally both methods does the same thing but my method is much better when you put the odds.
Sorry, missed updating this issue before. This is fixed in the current release.
Most helpful comment
For SP I'd rename it to something else as disconnect fits MP servers better..