As things stand at the moment, if you are caught offline and someone raids your fief, then you stand to face a total defeat as they fight your troops at vastly superior numerical odds, and then use the next battle to fight defenceless peasants. Obviously there is the whole, defenders can be resupplied thing, but I still find it imbalanced that a fief can be left virtually defenceless just because the owner wasn't online 24/7.
I'm thinking that a new action could be added to fiefs that are being raided, in which the idle population is ordered to "prepare for the coming raid", in practical terms this would mean that they begin securing the gear of the fief in hidden places, where the raiders will be unable to find it. The amount of gear that is safely hidden away by this method would depend on how quickly the action is selected after the raid is declared.
As a seperate feature, but one that I think could be linked to this in the idea of fairness (i'm thinking some might disagree with the above if the defence can use all gear but then it all be hidden from attack) :
Fief inventory could be sorted into "Armoury" and "Stockpiles" or something like the, the gear in the armoury is what the raid defenders will have available quickly to repel the raiders, and this gear will all be taken by the raiders should they succeed. The stockpiles, however, are what the villagers will begin to hide after the first action is selected, it will play no part in the raid but will be safe. In the event of a full siege, both armory and stockpiles will be available for defence and looted by the attack should they take the fief.