Not really. We would know people by proxy and referral through other real people. Like how real life works. And actually, over a large duration of time, the real nature of people eventually surface - even the nature of those who successfully pretend to be someone else that they are not. I dont expect that it would be different in the case of AI - it should actually be easier to tell that an account is an AI in the long run. Real people are rather sticky in their ways and character for large durations of time. Their quirks show. The AI constantly evolves and changes.