Boards of Review can become points of contention. That is not their purpose. The best means to avoid conflict is to know the rules from the Guide to Advancement (2015) well.
Since Troops, Varsity Teams, Venturing Crews, and Explorer Posts can hold them (troops exclusively up to First Class, see sec. 18.104.22.168), these are the general rules through Life rank.
Here is the key part that you need from the Guide to Advancement (2015) (underlining added for emphasis in text):
22.214.171.124 Particulars for Tenderfoot Through Life Ranks (or Palms)
The preceding applies to boards of review for all Boy Scouting ranks, but there are a few differences for the ranks other than Eagle, and for Eagle Palms:
- The board is made up of three to six unit committee members—no more and no less. In units with fewer than three registered committee members available to serve, it is permissible to use knowledgeable parents (not those of the candidate) or other adults (registered or not) who are at least 21 years of age and who understand Boy Scouting’s aims. Using unregistered adults for boards of review must be the exception, not the rule. Registered committee members familiar with the unit program, who have had a background check, and who are Youth Protection trained are preferred. Scheduling boards of review when and where committee members can attend usually alleviates the problem of not having enough committee members for a board.
- For a Varsity Scout team, the committee member responsible for advancement, the advancement program manager (youth), and the Coach serve on the board. Composition for Boy Scout rank or Palm boards of review held in Venturing crews or Sea Scout ships is the same as that for Boy Scout troops.
- One member serves as chair. The unit committee decides how he or she is chosen. The chair conducts review meetings according to BSA procedures and reports results to the unit advancement coordinator.
- The location should be comfortable, such as the unit meeting place, a camp, or a leader’s home.
- The review should take approximately 15 minutes, but not longer than 30 minutes.
- Ranks and Palms shall not be presented until the signed advancement report is submitted to the local council.
- If a Scout is to be reviewed for more than one rank (Tenderfoot, Second Class, or First Class), each rank should have a separate board of review. While these boards may be conducted on the same date, it is preferred—if feasible—that different members be involved on the boards to give the young man an enhanced experience and an opportunity to interact with a variety of adults.
Just run to the books where you have questions.