What is wrong with this?

OK, I know this photograph is not particularly interesting from a composition, lighting or jaunty and funny angle. However I did not have a pictorial record of either of my daughters getting on the bus for school, and thought that, as it wasn't raining for once, I'd grab a quick snap. This picture is taken with a 13 year old, fixed-lens, 5.1 megapixel, Sony camera, with no lens hood, about 80 yards from the public bus stop and depicts the bus, my daughter getting on it and 2 members of the general public about to board it too. I was standing on a public footpath. The background has part of my house in it. It is a public bus service which doubles as the school bus. The driver and I know each other as we exchange a wave as we usually pass on the road in the mornings. He is a fellow member of the local bowling club. Indeed after I took the picture he and I exchanged our usual wave.

The reason for publishing this rather unremarkable shot was that my daughter was removed from a class by the Deputy Head Teacher (who proposed a vote of thanks for a talk I gave along with some of my photographs at the local Rotary Club) and questioned her very closely on why her father was taking pictures of the bus, "as the driver had reported it"!

My feeling is that I have in no way acted illegally and the Deputy Head has no right to remove my daughter from a class to ask what I am doing in my own private time.

Discuss.