THAT would be cool, even if only to "enhance the experience". I sometimes use the promise of Glasses to get people off-guard at the end of the walk-thru. When people think the show is over, and start to offer compliments, I'd tell them, "You wanna check it out again next year. We'll be passing out 3-D Glasses, and bringing in a live Go-rilla from Africa, oh, it's gonna be REALLY scarey!!!" It makes them relax and sets them up for the final scare.