Faced with Lily charging at them, people usually had several options:
Fight back with fists and feet, then get pinned to the ground and beaten up.
Pull out their wand and resist after getting beaten up, get disarmed, then get pinned to the ground and beaten up again.
After getting beaten up, take the matter to the professors. The two sides would explain what happened, and the other person alone would get scolded by the professor, earn detention, and lose points.
Why was it always the other person who got scolded by the professor? Because Lily never made a move until they had met the standard that allowed her to beat them up for free.
And since these violent incidents always ended as fistfights, they rarely reached the professors. Fights of this level simply did not rank highly enough at Hogwarts these days. If the professors had to deal with every one of them, they would never have time to teach.
So, in the eyes of several professors, Lily was still the girl who only lost patience and struck out in anger once every ten days or half month after someone had offended her excessively. And she was very restrained in her attacks too, using no magic and only causing injuries that could be healed with a bottle of Potions—or even naturally, without any Potions at all.
Under such circumstances, wasn't it always the troublemaker who got scolded, docked points, and put in detention?
Thinking back on Lily's past behavior, Black could not help but shudder as he considered it carefully. She truly understood how to play by those rules.
Yet even if he saw through it, Black knew he could not do the same.
For one thing, no matter how much the other side insulted or provoked her before