For the record, I was stood up that end of the stadium, and the paper throwing didn't come from the far end where the lads with the drums and flags were, it came from the second & third bank of seats down.
The stewards were stood watching them do it, and didn't make any moves to stop it. In fact, one guy from around the third or fourth row hit one of the stewards with a ball of paper, and another steward simply told him to sit down.