4. Nothing shall be deemed to be an offence under this Act which is done in good faith-(a) for the purpose of promoting the welfare or interests of any member of a police-force by inducing him to withhold his services in any manner authorized by law; or (b) by or on behalf of any association formed for the purpose of furthering the interests of members of a police-force as such, where the association has been authorized or recognized by the Government and the act done is done under any rules or articles of the association which have been approved by the Government.