Not to beat on a dead horse, I'm just putting on my skeptic hat here....but what if I created this fake story by linking all the trailers and had my friend post it on IMDB and I pm'd it to you this morning....there is nothing to prove or deny the story....is there something else that was done to confirm?
You've got your events backwards. I initiated contact with this person as soon as the screening wrapped because I knew they attended, not the other way around. There's no way they're the same person as your hypothetical IMDB prankster.
Unless I'm in on it too!