That's an Althing-thing.
EDIT: BODs within Westmarch have two jobs:
1) an entity that can sign contracts with outside organizations
2) Oversee promotions of sub-lands.
3) A fierce dedication to the Pope
4) IIRC: To get a non-profit tax ID, a group must have 2 year's worth of BOD & financial records.
That's it.
Some kingdom BODs have turned into The Power Behind the Throne. I think having a shadow government is a Bad Thing. Not on my watch.
Having said that, I suppose getting a PO Box will involve signing something. I could sign it as:
*A guy acting on behalf of SG
*Monarch of SG
*BOD President of SG
I
shouldn't do that last one without approval from the rest of the BOD. However, I don't think anyone would be particularly offended if I did it anyway. You know... when I get around to it.