You would need ID Manager to have credentials expire, and that is licensed separately from your HiveManager and Aerohive devices. Based on the work flow you describe, where the guests credentials are forgotten and they have to enter them again to reconnect, that sounds more like roaming cache adjustments.
Once you connect, your credentials are added to the roaming cache in the AP you connected to and the APs near by, so you can roam between them and not need to reconnect. If you leave the network for a long enough period of time (you can adjust how long this is by adjusting the Roaming Cache Ageout), then they are removed from the roaming cache and would need to enter their credentials again to connect. Is that what you are looking for?
