Yakuake presently defaults its Open/Retract action to F12. At first startup, it displays a first run dialog with an info message, along with a KKeyButton that shows the glo- bal hotkey and allows changing it, which is also where the conflict checking takes place. After clicking Ok or Cancel in the first run dialog, the main window rolls out. On subsequent application startups, the main window re- mains hidden until the global shortcut is triggered to re- veal it (the shortcut is shown in a KPassivePopup in the screen corner at subsequent startups, unless it is dis- abled). The KShortcutDialog is only accessible through the main window.

Bottom line: If global shortcuts are made opt-in, that opt- in must be public API so that e.g. said first run routine can register the shortcut as active, even when the user dismisses the dialog with its default value (since the app won't be accessible without it once the window gets closed or during the next app session). If it's public API, how- ever, apps authors are going to do it anyway, pretty much screwing over the opt-in thing.