Assalamualaikum
A Deobandi Scholar mentioned that it is permissible for a female to travel more than 48 miles without a mahram if theres no fear of fitnah or theres haraj in taking a mahram like costs etc.The hadith mentions that a female should not travel more than three days or three nights,48 miles have been dedused through Ijtihad.At present its possible for a person to travel long distances through modern transport so if its within the limit of three days and three nights through modern transport,with purdah etc & no fitnah then it will be permissible for a female to travel,do you aggree ?