Proffessional ethics of a non-CA

As far as i know the ethics of a professional body are applicable to members of that body only. 

Hence a non-member of ICAI/ICSI/ICWAI is not bound by ethics of these bodies.

However if a tax practitioner gets regd. with some association of tax practitioners in his city/state, he may be required to abide by the rules of that association and also with other general laws of country.