The popcorn scene at the cinema
According from what the writer of the film said on the DVD this scene actually really happened...in the US.
She read that in a paper and decided to put it in the film.
They did the same thing in the film, Diner (1982). I was wondering if they stole the idea from La Boum, but maybe they both just sourced it from the same event that you mentioned.
http://www.youtube.com/watch?v=vujNcE_43Qg
Funny, I wondered at first what that scene was about - this video cleared it up.
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