If you used that password twice two years ago when you installed the module and you're suddenly pulled in an interrogation room in a foreign country? When you have about one chance to enter it right while some very angry officers look over your shoulder?
This is why usually these trigger-passwords are just a variation suffix away. If your real password was 123456 + Ok a system like that would trigger if you e.g. append a certain sign to it: 123451 + Ok. So you don't have to remember a different password, you just have to remember the one character or button that makes it call security.
