Something very similar happened to me, in that I was approaching a school bus from the oppossite direction, when she suddenly slowed and put the flashers on, with the stop sign being shown immediately as she came to a stop. It was very close, and I had only started to slow down when I realized that it was too close to be able to stop in front of the bus. There was very little warning and perhaps some confusion on my part as it was totally unexpected in that location ...
This was for pick up of 1 small child across the street waiting in front of a house ... at 4:00
This was a few days ago now (5) ... and I've been worried sick that she could of taken down my license number and the fear that I could recieve a large fine and points on my driving record !!!!
I would hate to have the fine and points on my record after having a clean record without any points/tickets for 40 years ... if she were to decide that I should of been able to stop in that situation ... 
Where would I find the exact wording as to when a ticket is issued to the owner of the vehicle or the driver, and if points are assessed against the driver that would effect my insurance premiums ??