You always think your imagined stories are "common sense". But what you are doing is cherry-picking the things you like. I could just as easily claim that Brewer told her about the look on the guy's face too. She was facing the other direction and said "what man?".
The things I like? What do I care whether she saw him or not?
Anyway...
"As I started back in the box office, Johnny (Brewer) asked me if I had sold that man a ticket. I asked him what man. He said the man that just ducked in here. I told him no, I didn't, but I had noticed him as he ducked in here." -- Julia Postal (affidavit)
Postal called the police...
"The officer asked me if the man fit the description of the suspect. I told him that I didn't know because I hadn't heard the description of the suspect. I told the officer that I would describe the man to him and that he could take it from there." -- Julia Postal (affidavit)