In the part where Jessica and her friends go to the club Instant Tang she holds up a wrist band that says "Over 21" when she goes to get the drinks for everyone. For her to have the wrist band she would have to show the bouncer at the front door her ID. Jessicas only ID is the one of her and a girl. And if she were to hold up that one they would say thats not "him" and she would have never have gotten the wristband.