sec.161, 164 of CRPC is funny. One could challenge such as witness tampering. The truth is a Hostile Witness is also proof of witness tampering.
Personally if I was a Witness to a crime I would refuse to answer any questions about it. Why? Because I would not want to be a party to witness tampering. I would merely state I saw the acts. If a Attorney or a Lawyer wants my testimony they will have to get me on the stand first.