Folks try to breathe.

UA can issue discipline to FAs who violate the Articles of Conduct, which includes issues such as adversely affecting United's relationship with its customers or repeatedly failing to follow SOP.

They just sometimes choose not to so that they can dedicate their resources to what they consdier more agregious infractions.

The union can file a grievance and represent the FA at a hearing or an arbitration, but if the case holds water, even the System Board of Adjustment is unlikely to overturn a termination for something the FA shouldn't have been doing in the first place (provided the company followed investigation and discipline procedures correctly).