@John: I know that the 72 hour wait period is basically a myth, but I am pretty sure unless there is evidence of violence or other reasons to believe the circumstances of the person's disappearance is unusual, they don't start after a person has been missing for a few hours.

In this case we have an adult female who went out on a date and is a few hours late coming home. Is it cause for alarm? Maybe. Will the police start an investigation based on that? Probably not.