In Moed Qatan 17a, the story is brought of Rebbi's handmaiden who placed somebody in nidui because she saw him striking his adult son. According to her, this was an infringement of the prohibition of placing a stumbling block before the blind, and the rabbonim uphold her decision.
According to Rashi, the reason that striking one's adult son is a prohibition of this principle is that doing so might cause him to retaliate, and then he will be guilty of striking his own father (a crime, incidentally, that depending on whether or not it causes injury might incur the death penalty). But this seems odd.
Granted: a person shouldn't hit their adult children anyway (they shouldn't hit people at all, for that matter), but is the reason really because otherwise their might retaliate?? Following that logic, does this mean that a rebbi should never chastise his students for fear that they might be guilty of answering back? If the halakha demands punitive measure of some description, why should we be concerned about retaliation?