CodeIgniter from creating a session for every visit

I am using sessions saved to database and TankAuth in CodeIgniter 2.1.3. The overall setup is that TankAuth checks to see if the user is logged in via

$this->tank_auth->is_logged_in()
This refers to libraries/Tank_auth.php

function is_logged_in($activated = TRUE)
{
    return $this->ci->session->userdata('status') === ($activated ? STATUS_ACTIVATED : STATUS_NOT_ACTIVATED);
}
which requires the session class to be initialized -- which will then create a new session in the database.

So I'm wondering if there's a way to circumvent this, because developerbook chatrandom my database is getting filled with empty sessions for non-logged-in users.

Any ideas/suggestions on how to tackle this problem?