Is it permissible for a woman to visit her husband in prison, located 240 km away, without a mahram, and with the rest of the prisoners' families on the same bus?

The majority of scholars are of the opinion that it is forbidden for a woman to travel without a mahram unless there is a necessity, such as migrating from a land of disbelief (dar al-kufr) to a land of Islam (dar al-Islam). Some scholars, however, permitted travel without a mahram when there is no fear of fitna (temptation or trial), even if it is not a necessity. If a woman needs to travel to her husband, and she cannot find a mahram, and her journey is safe, then there is no harm in her acting upon the opinion of those who permitted it.