People who have kids who go along with that are so lucky and I don't think they know that.
In my son's case, at 2.5, he believed me until everyone in the stretching room started screaming. Then he obviously felt that there was something incredibly wrong with me, because everyone else knew that this place was terrifying.
I hate that room and what people do. It's the one place at Disney where I truly dislike the people around me.
After the awesome introduction to the line (and to be clear I'm talking about
Disneyland specifically here but the concept is the same) it got worse. Dark line, people trying to scare each other, etc. By the time we got near the seating CMs DS was a mess. I asked for the exit. And then the exit was long dark corridors that felt like they would never end and an exit into an area with gargoyles. (Where DL's version sometimes has FPs set up at halloween time) So exiting was not a help.
The poster mentioned potc. At 4 my son decided potc was evil. At 5 (both of those years his birthday fell right over Mem Day weekend and one year was the free-on-your-birthday year so we went ON his bday both years) he snapped out of it and loved it again. Was really weird!
You know your kid but kids are unpredictable. Hope for the best but bring earplugs for the stretching room and choose who will exit with the toddler ahead of time.