Where I was sat the stewards were constantly informed, we had people wandering around in rag hats, Arsenal shirts and whole rows of people all cheering lustily when the scouse scored, yes there was bother because the tourists were telling everyone around them to fuck off.
You inform the stewards they have a thankless job of trying to sort it out in many cases it's the city support that ends up helping. So yes many people inform who they can, the point is that the people who are higher up don't seem to give a fuck.
The only police I saw doing anything were the ones helping rip the "Stop ripping us off" banner down, you know the important stuff?