During the movie, Star Trek: First Contact, the Borg were assimilating as many crew members as they could as they took over the Enterprise-E.
Picard watches a Borg drone lead a crew member away to be assimilated.
Borg Drone: Lower your weapons.
Picard: They will ignore us until they consider us a threat.
Two of the Borg drones walk right past Picard and several armed Enterprise crew members.
If the Borg want to assimilate as many as possible on the ship, why ignore several people?