I just want to say that as a family we love most of Halloween traditions. We have been decorated for almost a month, have carved pumpkins and made costumes, made crafts, and watched "scary" movies.
My kids- even my 13yo- still play dress up regularly and are in costume at school today even though most kids are too cool to dress up at their middle school. My DD who still has practice is actually missing a bday party in addition to trick or treating. To me however it isn't an important holiday, and they see their friends all the time. We get to be creative and have fun nearly every day of the year.
Maybe it's just "where we are" in our lives, but I pay almost $900 month for gym and dance and I refuse to waste a penny of it. To allow them to skip, to me, tells them that I don't respect the sacrifices we make (and they are many) to pay for it all. Their getting to be a kid means they get to do what they love and don't have to pay for it. They do have to respect that it isn't free or cheap. The candy part is incidental. On halloween in the past they have trick or treated and then sold the candy to their dentist.