Shooting in a gymnasium 09/02/15

Was ask shoot a volleyball game last night with my not so sports camera and I didn't say no.  My first challenge was my camera has always been setup to do portraits and landscapes.  I have back button focus which cause me to have a two step process with 2 separate buttons (focus first with the back button then shutter release) which is a much slower way of shooting in the beginning.  However, if you are shooting subject that are not moving it can be quicker.  Focus once and then shoot away.  So, I placed my flash on the camera, dialed the flash down to 1/16 power because I didn't really want to have a lot of flash in the shoot and ISO, set to 3200.  First shoot before the games started was with flash way to much so I just pointed it up but left it on the camera in case I needed for something.  During the next to last game a school official told me that I couldn't use my flash (5 games later) so as I was taking it off she said with a straight face.  "It could blind someone"....lol  I looked at her and the the flash I said it's pointing up.