From the ANB/ANS Constitution - Charter:

Section 3. Local Camp Charters. Upon application to the Grand Camp, established in Article V, below, by at least seven persons who qualify for ANB or ANS membership, and with approval by a majority vote of the Grand Camp, a charter shall be issued for the establishment of a Local Camp. Such

Local Camp shall organize and operate in accordance with the Local Camp Constitution and Bylaws prescribed by the ANB and ANS.

Therefore - Every local camp must have a charter and be in good standing with Grand Camp to remain a part of the ANB.

There are provisions to withdraw charters:

Section 4. Withdrawal of Local Camp Charters. If the Grand Camp determines that a Local Camp is in violation of the Constitution or Bylaws of the ANB and ANS, or that its actions bring harm to the ANB or the ANS, the Grand Camp may, by a two-thirds vote by ballot, withdraw the charter of that Local Camp, provided that the Local Camp is given the opportunity to be heard prior to the vote on withdrawal of its charter.