I personally wouldn't have an issue with giving out candy to little ones whether they were staying in FW or visiting from another Disney resort. After all, we visit many different resorts when we go to Disney. All Disney resort guests are welcome to the Campfire Movie as well as to the restaurants (although why they'd make a trip for the Trails End..I have no idea.
Guests from all the resorts come to the Fort for the BBQ and the Hoop Dee Doo. I don't see the Trick or Treating on property as any different. They're not pool hopping or God forbid
..filling up a mug from a different resort.
I can see being annoyed with people who live locally and aren't staying on Disney property coming by just for the treats. Yet, even there, I sympathize when in this day and age, there are so few places where you can let your kids go and have some good old fashioned fun. I'd just plan on buying some cheapo candy to give out...Save the good stuff for kids you know. Really I've found kids don't care about the candy (as much as the parents do
) they just want to share in the fun of Trick or Treating. JMO
...but what do I know.