> I am scared and this close to setting up a secret passphrase in case they need to tell me appart from a clone.
do that sooner rather than later.
Voice mimicry is so much easier now, that you might not be able to tell from the phone. This is why a verbal password from family is important, esp. in unusual situations.
while ostensibly true, the more different types of passphrase/words you have, the less easy it is to remember.
You probably only need just one, for authentication purposes. I doubt grandmother can perform this sort of "spycraft" well if it's more complicated. Better to have something simple and easy, than to forget and panic later.
do that sooner rather than later.
Voice mimicry is so much easier now, that you might not be able to tell from the phone. This is why a verbal password from family is important, esp. in unusual situations.