What is the legitimate legal control for dealing with widespread customs that violate Islamic law, such as shaking hands and intermingling in transportation and speaking with female relatives, given the increasing leniency in this regard?

Permissiveness in dealing with foreign women is fraught with danger. Islamic law prohibits seclusion with foreign women. The Prophet, peace and blessings be upon him, emphasized the danger of the "hamu" (the husband's non-mahram relative). Islam also commands men and women to lower their gaze and guard their private parts. It is not permissible to shake hands with a young foreign woman, because touching her is more forbidden than looking at her. Speaking with foreign women, such as a paternal or maternal cousin, is not permissible except out of necessity, and with Islamic guidelines, including: lowering the gaze, avoiding seclusion, limiting the conversation to what is necessary, and ensuring the speech is free of suspicion and lust. Permissiveness in speaking with foreign women may lead to indecency. Jurists have forbidden speaking with young women for fear of temptation, and disliked initiating or returning greetings between a man and a young foreign woman to ward off corruption.