There should be some guild warehouse space assigned for heirs. So that explorers can't withdraw from those slots.
It will help guild leaders to keep their expensive items safe from scammers like unity pots,stamina etc. Not much but only 5-10 slots or it can also depend upon leader that how many slot he want to keep for heirs in warehouse.
As a part of warehouse scam I will say that scammers mainly joins any good guild by saying that he is XYZ and it is his other char and some one finally invites him. After getting invite he finally asks for rank change and finally he withdraws expensive items and leaves guild.
I hope it will help a bit.