What is the ruling on a woman sitting next to a man on public transportation, and is she considered ignorant or heedless of what might result from that, such as the arousal of lust or falling into forbidden acts? And does the same apply to the niqabi, who is supposed to be an example?

A man sitting next to a non-mahram woman, and vice versa, in public and private transportation, is a great temptation. The original ruling in this matter is prohibition, as it places one in situations of doubt and temptation, which the Prophet, peace and blessings be upon him, warned against.

If a Muslim is compelled to use mixed transportation, he must fear Allah, avert his gaze from what is forbidden, and not sit next to women, even if he has to stand. If he feels temptation or lust, he must move away or get off.

It is not permissible for one who knows the religious ruling to violate it, nor for one who sees a reprehensible act to remain silent about it, especially those who are religiously committed, because they are role models. Their silence or participation in a reprehensible act is an endorsement of it, and their participation in it is a deviation.

As for the justification for doing what one believes to be forbidden, it is the weakness of faith that leads to indifference and frequent falling into sin, which makes it easy for sin to continue and difficult to abandon. Sins weaken the heart's desire for repentance and strengthen the desire for sin.