When my daughter was little (4 years old to 12 years old), I would accompany her and her friends. They would go up to the door alone, but I would stay at the end of the walkway to ensure her safety.
We live in a large city and she is turning 15 in a month. I still will not let her trick or treat on her own or with friends. There are too many dangers in our neighborhood. She is not interested in trick or treating this year, but as she ages she might be interested in having a party, hanging out with friends at home, watching spooky movies, etc.
Unfortunately, there are not many kids out and about these days. It is so different from when I was little. I miss seeing the kids in their costumes having fun. That doesn't mean we can't make the day fun anyway though! :) Happy Halloween everyone!