In most cases wouldn't that session info be tied to physical hardware to which the employee no longer has access? Sure, tick all of your boxes, but I would think that losing the company laptop/phone/VPN would be a pretty significant barrier to maintaining access to other systems.
I refuse to BYOD, so I am not familiar with the nuances, but wouldn't the corporate controlling entity wipe/reset/deauthenticate the corporate partition of the device?
