Anonymous users and presence subscriptions

Hi,

How are anonymous users and their presence subscriptions usually handled?

We run into issues with the following sequence of events:

  1. A customer logs in as an anonymous user

  2. The customer subscribes to some of the employees in order to receive presence information

  3. One of the employees subscribed to is offline

  4. The customer finishes, unsubscribes from the employees, and logs out

  5. Later, that offline employee logs in and receives the old subscription request

  6. Because this employee does not know the customer has logged off, he accepts the request.

  7. The employee never receives an unsubscribe message so the subscription sits in his roster forever.

Any thoughts and ideas are appreciated.

Thank you,

Matt