GMs can't do anything about items. I've been told this before by GMs in game.

If someone raids the FC chest and takes everything and leaves the GMs can't do anything about it because 'they were given the chance to'.

If you share a house with someone and they take all the furniture, it's because 'they were given the chance to' and GMs won't cover any of that.

The most that happens is the person who took said things gets in trouble, but items can't be taken away/given back in any scenario that I've personally seen. And with how the rules are, people still 'have a chance' to take loot that they shouldn't have upon a pre-agreed group.