If a child is wearing a homemade costume, be aware of the type of material you choose. Place reflector tape on your children's clothes and your own for that matter. You can find the tape at local discount and fabric stores. This will help drivers see you and your children more easily. If at all possible use non hypoallergenic makeup on your child's face instead of a mask.
Masks tend to fall off and block vision.
This also will give children a chance to be creative and come up with their own costume ideas. Only approach houses where the outside light is turned on, a good sign they are expecting children. Parents need to check candy when children get home. Tampering is rare, but better safe than sorry. Throw out any treats that appear questionable.