I agree with most of the above. If you have a reminder system in place and spoke with the client personally the day before to remind her, then she really has no manners.
I agree with sending a notice to all existing clients, and including this on your menus if possible going forward, that you have a cancellation/no show policy. I am a nightmare for remembering appointments, but if i've had a call/text the day or so before hand it jogs my memory.
A reminder system is worth it's weight in gold, but as you already have that in place, all you can do is try to put in place a system to reclaim your losses. I used to work for a salon who stated they had cancellation charge, but never charged it. When i asked the manager why, she said it wasn't worth it as they wouldn't pay. The salon went under and was sold. Personally, I would have invoiced every single person who didn't turn up for their appointment unless there was a valid reason (i.e sick ect). I would have chased it as well. I will be making a point of confirming with my clients when they book that I have a cancellation policy as missed appointments can cost you a lot of money!