In some situations, it would be convenient if one could use tladm to disable more sessions on a specific agent host. This would help if system administration is going to take place on the host, or if there are suspicions about the host being broken.
This doesn't necessarily have to be done using tlwebadm. A tool like tlctl could also be used for something like this.
A use case for this is if the admin wants to slowly start emptying an agent before doing upgrades or other changes to the host. Stopping the 'vsmagent' service would result in the master thinking the agent is down. This, in turn, would when reconnecting to sessions on this agent cause the user to be prompted to abandon the session. Removing the agent from the configuration will probably achieve the wanted result, but might feel too "permanent" to the admin. The practice of doing this for this use case was documented in bug 7610.