Along these same lines, we attended a Tom Petty concert a few years back at the Cynthia Woods Mitchell Pavilion in The Woodlands, TX. The pavilion is an outdoor amphitheater that has seats "under the tent" toward the stage, a grassy hill for the upper two-thirds or so, and a total capacity of about 22,000 folks. We sat mid-way back of the seated area from the stage and were surrounded by what seemed to be between 40-50 year-olds. In Texas one can drink in your seats but cannot smoke. That must be done in designated areas.
Us, being in our mid-forties, are the "stand-up-and-rock" sort, and prefer to spend almost all of our time that way while the bands are playing. After about four songs or so, the couple behind us tapped my wife on the shoulder and asked if we would kindly sit down so they could enjoy the concert too. What transpired shortly thereafter was a basic "we paid over $100.00 a ticket for these seats and we want to rock, so if you don't like it leave" conversation. The couple didn't like that response then enlisted the aid of the security personnel who politely told them that as paying patrons we had the right to stand or sit at the spot we were ticketed for. They were encouraged to stand or take refuge in the lawn area. We remained standing, and enjoyed the concert thoroughly. Love tom Petty.
Check the fine print on the back of your ticket. There is nothing there that says you have to sit in that seat regardless of its location in the venue. So, stand up, yell your ass off, and if the folks behind you don't like it, it's merely bad luck on their part. They need to chalk it up as one of those "I guess I should have bought front row tickets so no one is in front of me" moments in life. You paid hard-earned cash for those tickets (or somebody did) and you can use that real estate for anything accept for that which is illegal or breaks stadium policy while you occupy them. Screw common decency and politeness, you rented that spot for three hours. Enjoy it however you like.
Now, I would take a peek behind me to see who I was blocking. If it was an able-bodied person, screw 'em.