The fine print on the No Boo Necklace.
"Necklace does not garuntee a scare free evening.
Our monsters will do their best to avoid you, but some initial contact may occur.
No Boo necklace may not be worn in houses and on rides."
Way back I've heard of some regional parks doing something like this. It's definitely for kids and those who were dragged to events like this that might not be for what it entails.
Personally, I think this type of item is better utilized at theme park haunts which are included in general admission where you have a bigger cross over of regular guests and haunt guests, rather than a hard ticket event which is upfront on what you're getting into. (Let alone one where there's what, two rides for those who arn't into the haunt stuff.) But it'll be interesting to see how this turns out.