The place I go does the same. The reminder call actually comes 48 hours in advance to give you a chance to cancel. If you actually intend to go back after the no show (many don't) you have to pay first. No payment = no more appointments unless your clinician makes an exception. If there's a legit reason or your T knows you well enough they will give you a break too. I think it's pretty fair given that there are a lot of people waiting for appointments and many people go to T once or twice only to never go back.