No, so long as one puts in the full effort. If some punk just walks from door to door in everyday clothes and expects to get free candy, then people got every right to deny 'em. But there are plenty of teenagers and adults who really love Halloween, and spend a lot of time and money putting together awesome costumes, and really get in character. Those people should be able to trick-or-treat as long as they like. One should never be too old for the holidays.