I like to take the other side of some issues as a possible service to readers. Possibly even giving you another perspective to consider. I keep reading this post and it keeps bothering me. The best I can figure it is venting due to a distaste for the Army. I started to answer once but deleted before posting because I though my post would just be taken as hostile. It is possible that I am completely misreading this and you really just feel robbed of your ticket price.

How do you know he was Army First SGT and a pro photographer? Did you ask him? Was he in uniform? "there was an Army First SGT taking photos. He was supposed to be a professional photographer."
Did you know him prior to the event?
Did you ask him to tone it down?
Why would the Army be so interested in getting pics?
I'd be curios if you know what a "First" SGT is if only learning this via the uniform.
Maybe this guy just got back from killing people in Iraq or Afghanistan and this was his way of coping and detoxing from the horrors of war. (if USA or ?)

I find it hard to believe this was posted as a service to friends and relations needing to learn better via this forum, as you state: "Now, I expect the friends and relations of the pipers to take a couple of flash photos at a bagpipe concert. That normally occurs. They don't know better."

I have never heard anyone till now say only friends and relations don't know better.

Apparently you do not know better as you say you would have also done the same thing: "There was one part of the concert that I would have considered using a flash, if I was close enough to the stage for the flash to do any good.

If he behaved like you describe why did the workers not intervene?
Surely the theater people too must have noticed such extreme actions.
Where I live people would have spoke up about such extreme actions.
"he was running up and down the
isles, and he was doing something that anyone who has attending more
than one or two plays or concerts, or any kind of theatrical event
figures out in a hurry knows not to do - he was walking in front of the
stage to shoot his photos. He would walk out to the center of the
stage, and pop off a photo using the flash, right in front of everybody
like nobody was in the audience. Like he didn't care about everyone
who paid for a ticket to the concert."

I keep reading this post and it keeps bothering me.