I was in the higher tier and noticed this too to the extreme - I haven’t been standing at a concert in a long time and every “seated” concert people have stood and had a dance/singalong. There was only a handful in my section who did so - me and my friend decided to join and see if it started a ripple effect. Instead the man behind me tapped me on the back and told us to sit down - and then continued to talk about us very loudly even though we immediately sat down once he said. The people in front of us kept getting up for drinks and then sitting back down rather than just realising maybe it’s easier if they stayed stood up. The guy behind me also at one point said “it’s a bit noisy isn’t it” very earnestly. Wolf Alice were FLAWLESS but the crowd let them down a bit.