I won't be reviewing her as I've never met her. However that doesn't prevent comments based on general principles surely?
We can only guess what happened, but if she was faced with the choice of a late runner / possible no-show, or a walk-in requesting immediate service, then she'd probably take the immediately available money. Once the appointment time has passed she has no guarantee as to whether the booked punter will show or not.
==edit==
the above was posted before I saw your amendments.
Yes I now see she has a history.