After she testifies at Dr. Sutton's trial, Dr. Warner can be seen sitting in the gallery observing the rest of the trial. However someone who is a witness in a trial is not allowed to be in the courtroom, except for when they are on the stand. This is to prevent a witness' testimony from being influenced by other witnesses testimony, to reduce the number of opportunities for the defendant to try and intimidate a witness and to prevent witnesses from talking to each other and change their version of events or "get their stories straight".
When Chester Lake was interviewing the diner worker, he was told the victim stiffed him on the check. Chester than asked did he use a credit card and the worker went to find the receipt.
The diner worker remembered the victim as a regular, the worker probably went to get the receipts (plural, like he said) from some of the victim's other visits.
The diner worker remembered the victim as a regular, the worker probably went to get the receipts (plural, like he said) from some of the victim's other visits.