Just as I have a few minutes grace at the end of the day I have the same at the beginning in the sense that some days things just go right like the lights are all green, or there is no traffic at the four way stops or the kids don't dawdle as much getting into the car. There are lots of reasons to be 5 minutes early. But that is the grace period. Any more than that and we need to talk.

If you are one of those that lives by the clock for operating hours then I like the idea of a light on in the entrance way with the idea if parents arrive and light is off they should stay in their cars till it is on as you don't need them ringing the bell over and over either. No light not open, light on come on in.