If you use IsInteractionAvailable/IsInventoryInteractionAvailable to control cursor types, or which verb is to be used, etc. It means that that hotspot/object/inv/char etc. ALWAYS will have that interaction available, even if later it does nothing (after you've clicked it already, maybe). It would be nice if there was a way to disable an interaction, or if the automatic ClaimEvent that occurs in such situations can be turned off and authors would have to always claim events manually.
Interesting point. The problem with adding a feature like this is that I can see it leading to lots of people asking 'why doesn't my interaciton work??/?/?' when they forgot that they disabled it.
This suggestion could also be made redundant if custom properties were changable at runtime - that way, you could have a 'enabled' property or something which you could use to flag a hotspot as not interactable.