Its been said a million times, American footie, they can throw a red flag onto the field and have them check the video footage to get a decision correct, the refs in american footie only get 30 seconds of multiple video angles, if they can see something to change the decision, they do, if they can't they don't.
They only get 2 red flags, if they made the right decision and its not overturned, you lose a red flag, if its right, you get the decision fixed and keep the red flag. IE if you waste time by throwing the red flag needlessly, you might lose both red flags then come up against an obvious penalty the refs got wrong and be unable to challenge it. Sure the video footage would be used extensively for a few weeks, but it would dramatically, and undeniably reduce cheating to such a massive extent that most cheating would stop.
IE if people get caught pulling at a corner they'll concede a penalty, we'll get 3 weeks of the funniest most exciting games with an insane amount of red cards, then games with mostly no cheating, mostly no diving, mostly no pulling during corners and so on.
TOday was a prime example, Juan scored his header but if he didn't it should have been a penalty, one of the Chile guys was behind lucio with both arms around his waist in a bear hug and the Chile guy leaned back, sat down and pulled Lucio towards the ground.
Its as clear a foul as you'll ever see and they are ignored every game all game, it would dissappear in a couple games max.
Theres no reason to not use video footage and theres even less reason to not use a couple camera's in the goal line.
As for footage starting riots, the chance of a team starting a riot after a DODGEY decision is infinately higher than the chance of a riot starting after video replay shows if a decision is correct, or if its wrong and gets overturned, because those are the two options.
The two situations that might send fans over the edge are conceding a goal and thinking it was the wrong decision, or having a goal denied and thinking its a wrong decision, either way if fans are shown the decisions were correct theres a far far far lower chance of fans going insane.
As said, we'd have 3 weeks at the beginning of the season of mayhem, of hilariously long games, loads of yellow and red cards, loads of penaltys...... I can't see any downside, can you? more entertaining football, hows that bad.
After a few weeks of players realising they just can't get away with cheating at all anymore, well its simple, players will stop diving, stop cheating, stop pulling, stop asking for yellow cards, stop surrounding the ref(bad calls will be for the manager to call a red flag or not, where would be the point in players surrounding the ref when its the manager who would throw the flag or not?). So we'll have 3 weeks of the funniest games ever, followed by years, decades, centuries of fair football with a hugely lower number of mistakes, which means small teams will get the penalties they deserve against the big clubs, the whole league will be fairer, the Boltons of the world can't kick a great team off the park and a fancy flair team can't dive the other team off the park either. Its win, win, win win, win , win all around. The fans, the players, the officials, the regulators, everyone gets a better fairer game out of it.