I wish the issue was only with the smurfs. Basically, the WT frowns on anything of a mystical nature. Papa Smurf was a wizard - end of story. I used collect them (before the hoopla) and I even had a wind-up Smurf. I can't tell you how much self control it took for me not to bring it to the hall and make it walk down the aisle. It would've been hysterical - but I was too chicken to do it.
Witness children aren't usually allowed to watch - Wizard of Oz, Snow White, Cinderella, Little Mermaid, Harry Potter, Power Rangers, and the like.