[kmeisthax]

There's one flaw in your scenario: if your computer suddenly stopped respecting valid credentials, it'd be extremely obvious that the motherboard had been replaced or tampered with.

Generally speaking most evil-maid attacks assume that the attacker wants to remain covert, otherwise the victim will start revoking stolen credentials, calling the authorities, etc. If you don't care about remaining covert then you don't need to do an evil-maid attack; just buy a wrench.

[josephcsible]

The evil maid could use the credentials within seconds of you typing them in, so you wouldn't have time to revoke anything. With rubber-hose attacks, you might give the attacker a duress code rather than the real password, which wouldn't happen with this one. And let's face it: it's probably nation-states that would do this kind of attack, so calling the authorities wouldn't be helpful anyway.