You're probably right, that she didn't try. I can imagine someone reporting the story being content to let both sides state their own case, without "editorializing" by trying to see whose story checks out, especially with a deadline.
Is it possible that the student (Stuart Blessman) really did have tickets to this event? The only "upcoming showing" that I can still find is the one at Biola University (which is probably postponed or cancelled too, and just hasn't gotten around to updating the web to reflect it). They say they're "no longer" mailing tickets, and you can pick them up at "Will Call." So it seems to me possible that he did have physical tickets, even though PZ Myers just had a promissory email. It's also possible that Blessman's recollection of the "disturbance" is more of a false memory than an outright lie. Myers says he left the line to get copies of the release form, and others in line asked him for copies. I can see witnessing this interaction and thinking nothing of it, then spinning it later into a "hustling or bothering several invited attendees" memory when it became significant. Of course, there is still the possibility that he's a "shameful liar," but I'm inclined to give him the benefit of the doubt, and say he's merely mistaken.
It would be nice if reporters could sort it all out for us, but then we wouldn't get as much practice exercising our critical thinking skills.