"Necessity defense" is an actual legal concept. My local law for example defines it as:

Conduct which would otherwise constitute an offense is justifiable and not criminal when: Such conduct is necessary as an emergency measure to avoid an imminent public or private injury which is about to occur by reason of a situation occasioned or developed through no fault of the actor, and which is of such gravity that, according to ordinary standards of intelligence and morality, the desirability and urgency of avoiding such injury clearly outweigh the desirability of avoiding the injury sought to be prevented by the statute defining the offense in issue.

While in principle it is meant for situations like "aggressively pushing someone out of the way of a runaway tram", it has been successfully used by protesters to get acquitted for acts of civil disobedience.

More power to her, we need civil disobedience to effect change.