cybereality
The problem with that logic is that an avatar has no real connection with your identity. I suppose you could say that spam accounts are less likely to have an avatar, but I've seen some that had them. The only clue you actually have to someone's identity in a chat environment is their words. Everything else is much easier to fake, even without advanced software.
Besides which, does it matter if someone you speak to remotely is who they say they are? What would you do differently if they weren't?