Here is the report. What a learning experience!
I totally failed with the lens I selected! I went with a preconcieved idea of the function and did not do proper research. In past all her school functions were in the open and parents were at a considerable distance away (something like KeithBreazeal photo). I found myself in a dimly, very dimly lit indoor auditorium. Felt like banging the Sigma 150-600 f5 on my head. 70-200 f2.8 would have been the appropriate lens - opening wider by 3 stops, smaller, correct focal length. Bumped up the ISO to 6000 and still getting 1/15 shutter. Damn. Note to self: Must do proper prep and not be an idiot.
I was amongst the early ones and was pointed to sit in the second row from front. Not good I kept telling myself as the lens could block the view of people behind me. But since I would not have to stand up, it would be more or less ok.
The girls started walking in from behind me walking through the isle towards the stage. I could not get any photos as I was totally immobile and at 1/15 all shots with any movement were going to be useless anyways.
The ceremony started and I realized that the official photographer was strictly doing what he was there for: 1 single photo of the girls receiving the certificate. I steadied myself and took some shots.
You be the judge if me taking the camera was worth it or not. I know with better lens choice I would have had better photos.
A note before I post the pictures, the daughter met me in the evening and hugged me and said thank you for the photos (I took of her friend's also, many of who have posted them on their face book page). I asked her to see this thread and her first response was "Oh you and this Canon Rumor 'thing' again? Don't you get bored?" She read all the comments smiling right through, occasionally giggling while shaking her head in agreement. And then she asked me for money to go out with friends for dinner. So am not sure if the hug and all was true or a ploy get the car and dinner money. Hmmmm.
Here are the pictures, it is obvious which is the one taken by the school photographer.