When you're logged out of a virtual game, nobody can force you to log back in. But you can wake up someone who's sleeping.
Have you never set a game with alerts that make noise if something interesting is happening, so you rush back and play?
The delay in waking up is how long it takes the "player" to get back to his chair.
If the player did not go back that would be seen by us as fainting, or in longer situations, a coma.