There should be 1 owner of a house and he can give admin rights to other members. But how it is now where everyone can change lock codes is extremely risky.
You never know who you can trust. There were cases where someone joins your clan, and then a few days later all lock codes are changed and you cannot enter your base anymore. If everyone can change lock code and build, then any person who knows ur code can fuck up your house…
I think the best way to solve this would be, only the people who have cupboard rights in this area can change lock codes. So if I have a big clan, I would only give a few trustworthy people access to my cupboard, and only they can change the lock codes if needed.
If there is no cupboard at all in the area, of course everyone should be able to change lock code.