I believe this feature would work when the leader turns it on, hence: "All players to battle ford within five min" After the five minutes were up the leader would turn it on and lights would appear, green red and orange. Green in a base and online, orange offline and red online but not in a base. The leader could then quickly check for "slackers"

Definition of "Slackers": Someone who is not helping to base when they have been instructed to by leader/leads.