I hated Santa when I was that age, too. Why do people do that to their kids? Just skip that developmental stage when Santa freaks the kids out; resume the annoying holiday snapshot opportunity when they're a year older and better able to visualize the sugarplums.
Kids are supposed to mistrust strangers -- especially strange men in the mall who offer to take your picture and give you candy. And want you to sit on their laps. Ewww.