Does Message allow me to ensure I am talking to a particular person?

Question

Message:

You point your finger toward a creature within range and whisper a message. The target (and only the target) hears the message and can reply in a whisper that only you can hear.

You can cast this spell through solid objects if you are familiar with the target and know it is beyond the barrier. Magical silence, 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood blocks the spell. The spell doesn't have to follow a straight line and can travel freely around corners or through openings.

Alice casts Message towards a creature. She believes that creature to be her friend Bob.

The creature is, however, actually the villainous Eve merely disguised as Bob. Can Alice preclude Eve from hearing the Message?

Answer 1

Mostly no

You choose a target by pointing at it. There are no further general requirements; In particular, nothing requires the target you point at be identical to the person you wish to speak to.

Sometimes yes

When cast through a wall it only works if you're familiar with the target. Now, if Bob was walking behind some barrier, got knocked out and Eve used shapeshifting or illusions to look like Bob you would not be familiar with her, pointing in Bobs general direction you'd still reach Bob (who is presumably unconscious or otherwise incapacitated at this point).

However, if you've met the Eve disguised as Bob before, and she is now Eve disguised as Bob or even Eve not disguised as Bob behind a barrier, and you try to contact "Bob" (who is still Eve) behind the Barrier there is nothing stopping that from working. You're still picking a valid target, she's just not who you think she is.