Guild Wars 2

I only have two members in my Wicked Depravity guild, including myself, yet frequently when I check the History for my guild I see listings of multiple persons logging in. For instance the most recent is this one….. “3 members logged in 2/1/2015 for 30 influence” or similar history records.
How can anyone log into my guild besides my guild member or myself?

I have a two person guild, combined we have 11 characters. Both of us log in every day to build Influence for our guild. BUT.. some days we are credited with “4 members logged in” and other days with “8 members logged in”. Never 11. Is the influence measured by real life players logging in or by the characters we have? And why the discrepancy in the amounts every day?