Happy Halloween

Trick-or-treater count is at 10. A couple witches, a pumpkin, an ogre, a princess, and Spiderman. One set of three kids had underwear on their heads. They explained that they lost a dare. The first kid was pretty young and tried to get into the apartment. No, literally. When I didn't open the door fast enough (read = a milisecond after he knocked), he started turning the door handle. I open the door to see Mom at the porch with a video camera and Son saying "Happy Halloween" and then walking away before I could give him candy. He came back and was very cute and so on and so forth. But he tried to open my door! Something else I noticed: all the kids say "Happy Halloween" instead of "Trick or treat" now. When did this happen and why? Is this a PC thing? Is this to prevent lawsuits? Or is it just a Colorado thing?