The Extended inventory is often left unused, but the few players who use it don't have anything special on their profile indicating that they have items equipped on it. This means that if you don't want to miss anything about characters, you should have to inspect every player (with the delay to query and retrieve inventory) and often find blank inventories.
It should be automatically retrieved whether or not a player actually has at least an item equipped on his Extended inventory, and displayed as an indicator in some way (left for discussion at the moment, not sure the icons at the bottom of the tooltip are clear enough for that purpose).