To dream of trick-or-treating on Halloween represents your feelings about overlooking a negative, scary, or uncomfortable situation knowing you will get mandatory respect, love, or a pleasant experience. Knowing that if you put up with something scary that other people have to respect you or make you feel good.
To dream of trick-or-treating when it isn't Halloween represents feelings about yourself not having to do anything except show up somewhere or to be cared about. Being present at some location or will give you mandatory respect, love, or pleasant experience. Possibly a reflection of a visitation to family or friends. Feeling that people are happy to see you visiting them at all.
Example: A man dreamed of seeing someone trick-or-treating on Halloween day. In waking life he showed up at his father's house after having embarrassed his father in front of the whole family. He knew that his father would prefer to overlook the embarrassment and would respect him no matter what because he was happy to see that he visited him at all.
*Please See Halloween