When the gang is in the malt shop, the place is packed with teenagers.After Danny and Sandy leave, Kenicke and Rizzo have their fight and she throws her shake on him, and says "To you from me , Pinky Lee" then picks up her purse and says "Sorry French" and leaves.

A split second later, we see the waitress walking towards Frenchie and the whole malt shop is now totally empty. How could a restaurant full of teenagers clear out in a matter of seconds. What'd they do? Teleport?