Probably have the account linked to a specific code that's auto generated for the user within the client upon first connecting, and hoping they save this code when told to do so (a lot of people wouldn't) so idk! I feel like having it tied to an email is the best option overall, like any other game / site, steam is still tied to an account that has an email, so if we were to just use steam it'd be the same thing, just more annoying for the people that refuse to use steam. Though I guess we just don't force accounts, but if we don't force accounts what's the point anyways. I guess we restrict users that don't have an account, but that's essentially forcing them anyways?