In Once Upon a Time in America, Noodles informs the police about a routine booze crime operation that the band was about to do. He does so to save Max from getting killed when doing another crime Max was longing to commit — robbing the Federal Reserve Bank — by getting him spend a year or two in jail (where he has never been yet) so that he could realize what it is, have time to think and change his mind about robbing the bank. Noodles is ready to go to jail with Max for that.
However, it turns out that Max has had his own plot already arranged. The police (on his payroll) have been arranged to ambush their vehicle, kill the other two guys (Patsy and Cockeye) and fake Max's death.
That is, when Noodles calls the police to give them the "tip", that is no news to them — they are already prepared to do what they have arranged with Max. Max then tries to convince Noodles not to go to the booze operation and stay home, and when Noodles refuses ("everywhere you go, I go too"), knocks him out.
So, what did the Noodles' "tip" actually change?
Presumably, the police would have later informed Max about Noodles calling them (which, in turn, could make Max decide to kill Noodles). Noodles will then live 35 years thinking how awry his tip to the police turned out when in fact it changed nothing perhaps apart from Max trying to kill Noodles in revenge which made him run away.
Is this correct analysis?