The short answer: Because of how BallotBox protects the integrity and anonymity of your votes, you must have at least two Officers.
The more detailed answer: A “quorum” of Officers is the number required to unlock the results of a poll. By default, the quorum size is set at 2 Officers, unless you set a higher number on your poll’s Settings tab. The quorum must get together, in person, in front of the same web browser, to enter their passwords when you unlock your results. You will not be able to retrieve your results unless at least a quorum of your Officers remembers their respective Officer passwords.
For that reason, we recommend that you have more Officers in your Poll than the quorum size. For example, if you have the default quorum size of 2 Officers, we recommend that you have at least 3 Officers for that poll. That way, if one Officer forgets her password, the other two Officers would still be able to unlock your results.
You can have quorum of as many as 5 Officers.