There is only 1 reminder that is being sent by BK. It is the 24-hour reminder, but clients need to also have a 3 day reminder as well. This gives them time to reschedule or postpone in case they need to. 24-hour reminder will fall under the cancellation policy for most companies.
Also, it would be a nice feature to have control of how many reminders you want to be sent and at what time.