Plot hole: Just before playing the water glasses, Gracie plays a couple notes, one of which is very high. She drinks some water out of the glass to lower the pitch. The problem is that the pitch goes up when you remove water from the glass, not down. Drinking out of the glass would've made the note sound higher. Some people and websites will make you believe that the pitch is going down due to an increase in the size of the resonant chamber but singing glasses have nothing to do with cavity resonance. Glass singing is caused by the molecules in the glass vibrating in resonance with each other. More water dampens the motion, slowing it down and lowering the pitch. Some of the confusion comes from schools not teaching children that liquids and gasses are both fluids. In the case of water in glasses, the water is not changing the cavity as much as one thinks, just damping it. And finally, if you don't believe me, don't Google it, try it.
Plot hole: Grace is allowed to enter the Miss United States pageant as Miss New Jersey when it is discovered that the actual Miss New Jersey made an erotic film. The problem is, the Miss New Jersey pageant would have a first runner up who would take the winner's place if, for any reason, she were not able to complete her reign. Everyone in the New Jersey pageant system would know Grace had not been a contestant.