Wouldn't a client certificate from e2echat protect that kind of attack ? Since even when a man in the middle offers u a server cert u accept, the e2echat server

Wouldn't a client certificate from e2echat protect that kind of attack ? Since even when a man in the middle offers u a server cert u accept, the e2echat servers can't validate the client certificate from you anymore (Still bad but would at least protect connections from ever talking to e2echats servers)