Always put the matches from Brazil at the end of the day, force them to stay until the end of the event. End.
If they play first they all going to leave after watching their teams playing
Understand a thing, for you to go to a spot to another in São Paulo is like 1 hour (if there is no traffic) people need to eat, need to sleep, they can't be until 8 hours of the night seeing a game that will not change anything in their day a day life (because if they do, they probably only will arrive home until 11 p.m at home). And from what a heard, there's no food in the event, so people need to leave to eat, and in São Paulo to everywhere takes lot of time because of traffic (specially in the night when people are going back from work).
I'm not denying that there are people that will leave after their team play, but the fact that the Arena is a fucking oven during the entire day, there's nothing to eat at a reasonable price and you can't go in with anything is a big reason on why people are leaving too after their team's games. RIOT is the one to blame, not the crowd. On the LCQ LATAM that happened in that same arena had sound-cancelling cabins for the players during matches, all games were full, and no one had nothing to complain about the event. I don't know how they fucked up so hard when they got it right last time.