It is a basic principle of elections for Bahá’í Spiritual Assemblies that each voter must vote for the nine people who, in his or her opinion, are best suited to serve. He may have a low opinion of all those who are eligible, but his duty is to vote for those nine from among them who, in his estimation, best meet the standards for service on a Spiritual Assembly. This is how it is possible to vote for exactly nine names. Since the membership of an Assembly is nine, it would give rise to a number of statistical anomalies if voters were permitted to record votes for fewer or more than nine names. In any one election there are not usually any cases where a voter accidentally makes a mistake and includes a name of an ineligible person, so the statistical effect is slight, and there is no need to invalidate his whole ballot. As you point out, a believer who does not wish to vote for nine, may achieve his end by purposely including the names of those who are ineligible, but this would be a betrayal of the trust placed in him as a Bahá’í voter. One cannot control such actions, but like any action contrary to the spirit of the Faith, they are detrimental and should be strongly discouraged.