Every year since we've moved to Oak Park, we've wondered if we should say anything when grown people come to our door asking for treats.
On the one hand, we think "What the heck, it's Halloween, everyone gets candy."
On the other hand, we think, "What the heck is wrong with you that you come to our door, an adult dressed in adult clothes, asking for candy."
Usually the let's-just-call-them-"mature" trick-or-treaters simply stand there like kids holding their bags open, sometimes offering lame-o explanations like "My baby is in the car" or "I have a sick kid at home that I'm collecting for." Uh-hunh, maybe.
Halloween has no strict rules, so I'm inclined to just hand out candy to adults, with no (potentially embarrassing) questions asked.
One reason for just giving in and giving out candy is that people who are over 25 and still trick-or-treating may actually be suffering from some form of delayed developmental disorder, impulse control problems, or other psychological impairment. So I usually don't say anything to them, on the theory that it's best not to set off a lumbering, potentially imbalanced 250 pound grown-up on a sugar-high.
I believe some of our good neighbors have a policy of "no costume/no candy." I respect those who take this reasonable position, but I've never enforced that rule.
When OPRF HS kids come to our door on Halloween en route walk home after school, clearly not wearing any costume at all, I sometimes ask skeptically, "So, what are you this year?" Their usual, entirely predictable response is "A student."
Maybe I should ask the same what-are-you-this-year question to adult trick or treaters. If they answer honestly, it may force these overage goodie seekers to confront the fact that they are adults, grown-ups, usually parents, and so maybe they shouldn't be participating in a child's activity.
Or maybe they should be having fun wherever they can. I dunno. It's Halloween.