My 11 year old went trick or treating tonight and I am going to ground him because of it.
Why do you want to punish your 11 year old because of trick or treating?
I heard she is always misbehaving, does not listen to my instructions and I hate kids spoiling my house decorations.
If your child disobeyed the rules you have in place for her, it's fine to discipline her. Doing this will help learn that there are consequences for not following the rules or misbehaving.
You don't seem to care about punishing kids. What am i going to do when she's big if I'm not allowed to discipline her?
I am agreeing with you. She broke the rules and should be appropriately punished.