I also saw this one this morning which I like much better. It's a little business card your child can hand out while TorTing (LOL, Gretchen, when I saw you write this above I had to ask myself what torting was supposed to mean! Ah, gotcha). To me it makes more sense for the child/family to EXPLAIN why their actions might be perceived as rude, than to expect families with no idea about special needs to assume every single kid at their door (many of whom, quite frankly, are rude) has a special need.
This is the card:
Hello, my name is ____ and I have Autism. I cannot say "Trick or Treat" or "Happy Halloween," but I am trying.
Thank you for understanding and Happy Halloween.