Reply To: A mitzvah for an aveira? or at someone else’s expense?

My rov said mipnei darchei sholom, not to insult or embarrass another person by refusing to shake hands. Just do it quickly, firmly, and that’s is the end of it. Keep it businesslike, and don’t extend your hand first.

Also, I thought the inyan is that a man should not walk between two women, not vice versa. Can someone enlighten us?