[NoahZuniga]

That's protected cryptographically with key transparency. Anyone can check what the current published keys for a user are, and be sure they get the same value as any other user. Specifically, your wa client checks that these keys are the right key.

[morshu9001]

Even if your client is asking other clients to verify, what if everyone has the same wrong key for a particular user Whatsapp has chosen to spoof?

[NoahZuniga]

Well, surely your client knows what its own key is, and would notice that the listed key is wrong when it checks it.