feel the need to take off running to the next house. first off, running is not a good idea, and walking is more safe. secondly, if their costume is too big, they might trip on it and fall. plus, if it's getting dark out and your child has gotten far ahead of you on the sidewalk, it might be a little difficult to spot them in a large crowd of batmans and wonder womans.
make sure their costume fits them well, and that at least one element of their costume contains a bright color so it's easy to spot them - even if it's their trick-or-treat bag. might i suggest a 