It has scheduled times that it happens. A few days before you go check out Steve Soares website .Walt Disney World Live Entertainment He posts up the schedules for everything for the coming week on Fri-Sat usually. I typed them all out on little index cards that I took to the appropriate park with me. That is how we met some of the characters without much wait and knew where they were hiding.
I am going to tattoo it to the inside of your eyelids to "call Vix when I have a question" LMMEO