I have no patience for NCNS. At ALL! If they at least call I'll consider a reschedule depending on the level of stupidity of their bullshit excuse. I've said it before, I'm in sales. I make appointments all the time. Customers cancel on me all the time and I still have to call on them. But the first time I NCNS, I will NEVER get back into that account. It's the way it works. I operate the same way.
BTW, I've never NCNS a provider. I have canceled, as things do come up unexpectedly. But even those are rare. Most cancels from me are ones I set up days in advance and then the day of things at work/home explode. So I do get it. But I can honestly say that of all the times a girl has canceled on me, only a couple seemed like genuine reasons. Again, I'm in sales. I'm used to people lying to me all the time and have a finely tuned BS detector. Almost always the reasons, when distilled, came down to a provider being skittish (fine, but make me wait to verify BEFORE you give me an appointment), her being lazy (you mean I actually have to get dressed to see a guy....) or she schedules someone else into that slot (poor time management and a waste of my time!). I can see a girl taking a last minute 2 hour appointment from a regular and bumping me if I'm new, but there are good and bad ways to handle it.
But NCNS me, I have the same policy as I have at work. You're FIRED! In this day and age of email, text, cell phones there's no reason not to be able to communicate. And don't give me the BS of "emergencies" because like I've said, VERY few of those truly arise. And if they do, and I get a belated call saying "hey, sorry but this came up" I would evaluate it based on my perception of their sincerity.