| No; pumpkins are also used in Thanksgiving. Jack-o-lanterns are fine, though.
For clarity, Halloween themes include, ghosts, monsters, zombies, vampires, etc. They also include movie monsters such as Freddy Kruger, Jason Voorhees, etc. Spooky backgrounds and settings are also acceptable. Candy is fine as long as you have a trick-or-treater to go with it (That is, keep the candy in the bag. I don't really care how well you can sprite a gumball.).
-Dylan |