I mean, if you have other shit going on that day, it's kinda on you to cancel or reschedule your appointment before whatever cutoff they have instead of just not going.
You made the commitment to be at your appointment at the scheduled time, and if you no show that's time that could have been spent seeing another patient and money they can't make because of your actions.
I've never had an issue if something came up the day of and I needed to reschedule, as long as I called the moment I knew I might not make it.