I too have sent letters home as well as reminders of what time we leave in the morning. I have said, if you are not here on the agreed time, and especially before we leave, then I assume that you are not returning. I need to drop off bus students and then walk over to the public school. In the nice weather we often stop and play at the park, so if you miss drop off, who knows what time we will get back! It is the parents fault!