There's a YouTube video of an EMPTY carboy with the airlock bubbling away.
An airlock is just an airlock. It has an indirect correlation to active fermentation at best. The beer's done when the hydrometer says it is, not the airlock.
Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Florida Weiss
Primary #3 - Kane-DOH APA (Honey Citra APA)
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Raspberry Florida Weiss
Keg #2 - Cinnamon Raisin Cider
Keg #3 - NONE!
Bottled - NONE!